Soldering, Brazi 
and Welding 



Iazing, 



WITH MANY 
ILLUSTRATIONS J 



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OassXl2_kI 



Soldering, Brazing 
and Welding 



EDITED BY 

BERNARD E. JONES 

Editor of "Work" 



With 78 Illustration* 




FUNK & WAGNALLS COMPANY 

NEW YORK and LONDON 
1917 






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EDITOR'S PREFACE 

This handbook, which explains in detail a variety of 
processes common to general metal working, has been 
written by a number of thoroughly practical men, by 
whom it was contributed in another form to " Work," 
the illustrated weekly journal of handicrafts and 
mechanics. Its appeal is to everybody who makes any 
attempt at working in metals, inasmuch as at least 
one of the processes— soldering, brazing or weld- 
ing—will be met at a very early stage in the 
beginner's experience. This handbook will be found 
a complete workshop guide to the usual methods of 
soldering and brazing, and will form an excellent 
introduction to the modern electrical and oxy-acetylene 
welding processes, to do complete justice to which, 
however, a separate handbook would, of course, be 
necessary. If readers encounter difficulty in any of 
the matters treated in this book, they have only to 
write to ' Work," in whose columns (but not by 
post) help will be willingly afforded. 

B. E. J. 



CONTENTS 



CHAPTER PAGE 

1. Vaeious Processes of Joining Metals . 1 



2. Soft Solders ..... 

3. Fluxes Used in Soft-soldering . 

4. Soft-soldering with the Copper Bit . 

5. Soft-soldering with Blowpipe or Bunsen 

Burner ..... 

6. Soldering Aluminium .... 

7. Wiping Joints on Lead Pipes 

8. Hard-soldering with Silver Solder . 

9. Soldering Gold and Silver Jewellery 

10. Brazing ...... 

11. Welding Iron and Steel Under the Hammer 

12. Making Blowpipes .... 

13. Managing Blow-lamps .... 

14. Making Blow-lamps .... 

15. Electric and Thermit W t elding Briefly 

Considered ..... 

16. oxy- acetylene welding 

17. Lead-burning ..... 
Index 



4 

12 
17 

37 

57 

64 

75 

83 

89 

108 

112 

118 

122 

129 
134 
150 
155 



SOLDERING, BRAZING AND 
WELDING 

CHAPTEE I 
The Various Processes of Joining Metals 

Apakt from the use of rivets, screws, etc., metal is 
commonly joined by soldering, ' brazing, or welding, 
three groups of processes that have one thing in com- 
mon — the use of heat to fuse either the metals them- 
selves or an alloy which is interposed to consolidate 
the joint. The word " solder " is derived through 
the French from a Latin word meaning " solid." 

Soldering may be "soft " or "hard." Soft-solder- 
ing uses lead-tin alloys which are easily melted in a 
bunsen gas flame or with a hot iron or bit ; while hard- 
soldering employs a silver-copper alloy, to melt which 
a mouth blowpipe at least is necessary. Brazing is 
hard-soldering with spelter (brass), and a forge or a 
heavy blowlamp or a powerful blowpipe must be 
employed to provide the heat. 

Welding is a fusion process which in the past was 
almost entirely confined to wrought-iron and steel, 
these metals possessing the property of weldability to 
an extent unknown in the case of any other metals. 



2 SOLDERING, BRAZING AND WELDING 

The blacksmith's process of welding is to heat the iron 
or steel until the surface of the metal becomes pasty, 
and then to bring the two pieces into intimate contact 
by hammering on the anvil. Of late years the weld- 
ing of iron, steel, copper and some other metals has 
been rendered possible by the use of certain electrical 
and chemical methods and — most important of all — by 
the- use of the oxy-acetylene blowpipe, the process being 
known as "fusion welding " or "autogenous soldering," 
the word autogenous implying that the process is com- 
plete in itself and independent of the use of any 
extraneous ' substance such as solder. The thermit 
process, of which so much has been heard, and which 
is briefly dealt with later, is the fusion welding of 
iron and steel by means of the intense heat produced 
by the combustion of a special chemical compound. 
Perhaps the oldest of the autogenous soldering pro- 
cesses is "lead-burning," in which the flame of an airo- 
hydrogen blowpipe is brought to bear upon the lead, 
the joint being fed with a strip of the same metal. 

Soft-soldering is an operation that the beginner will 
not find nearly so difficult as hard-soldering or brazing, 
and although the strength of joints made by it is not 
nearly equal to that produced by the methods named, 
it fills a useful place within its scope. It is purely a 
surface union — that is, the solder adheres to the faces 
in contact in much the same manner as an adhesive 
sticks to metal ; but with the assistance of fluxes, the 
contact is made so intimate that some force is necessary 
to break the joint. Soft-soldering is also of use where 



PROCESSES OF JOINING METALS 3 



brazing would- simply mean the ruin or destruction of 
the metals, as in the cases of lead, poor-quality brass, 
pewter, tin, zinc, and in tinplate and galvanised iron. 

In silver-soldering and brazing, the silver or spelter 
that fuses to form the joint alloys itself so intimately 
with the copper or brass that it actually becomes part 
of the piece itself, and for all practical purposes 
cannot be distinguished from it. But soft-solderino- 
is not always inferior to hard-soldering. Indeed, 
the surface nature of the soldering often constitutes 
its value. 

The strongest joints of all are produced by fusion 
welding, as will be duly understood from later chapters. 



CHAPTER II 
Soft Solders 

A solder should melt at a slightly lower temperature 
than the metals which it unites, and Should possess the 
quality of alloying with the two surfaces, thus effecting 
a sound and true metallic joint. Ordinary soft solders 
are lead-tin alloys , and the larger the proportion of lead 
the commoner is the solder said to be. At an extreme 
is plumber's solder, consisting of 2 parts of lead to 1 
part of tin, and, at the other, the best blowpipe soft 
solder, which contains 2 parts of tin to only 1 part of 
lead. In the ordinary way, a "coarse " or "common" 
solder is 2 parts of lead to 1 part of tin; a "fine " or 
"medium " solder, 1 part of lead to 1 part of tin ; and 
a "very fine " or "best " solder, 1 part of lead to 2 
parts of tin. 

Eutectic Alloys. — Lead - tin solders are eutectic 
alloys — that is, they are examples of the phenomenon of 
a combination of two metals melting at a temperature 
lower than one of them would if melted separately. 
Thus, lead melts at about 328° C, and tin at about 
232° C, yet reference to the following table, given by 
Mr. A. H. Hiorns, will show that the "commonest " 
solder mentioned fuses at 303° C, and the "best " at 
175° C. 

4 



SOFT SOLDERS 



Tin% 


Lead% 


10 


90 


20 


80 


30 


70 


40 


60 


50 


50 


60 


40 


63 


37 


70 


30 


80 


20 


90 


10 



Melting points of lead-tin alloys 

Melting 
point (C) 

303° 
278° 
255° 
230° 
205° 
187° 
175° 
185° 
198° 
215° 

Hardness of Solders. — According to the before-men- 
tioned authority, Saposhniko, in 1908, determined the 
hardness of various lead-tin alloys by Brineli's method, 
by which a steel cone is forced into the metal. The 
results he obtained are as follow : 

Lead ... 100 90 SO 70 GO 50 40 34 33 32 30 20 10 
Tin ... 10 20 30 40 50 60 60 67 68 70 SO 90 100 
Hardness 3*9 10'1 12*16 U'o 1VS 15'0 14'6 16*7 15'4 14'6 lo'S 15 ! 2 13*3 4*1 

These results, says Mr. Hiorns, show that the 
hardest alloy is the one with 00° (about 2 parts) of tin 
and 34° (about 1 part) of lead, which also is the one 
having the lowest melting point of all the lead-tin 
alloys. The resufts also show that tin is slightly harder 
than lead. 

Compositions of Soft Solders. — As already shown, 
solders vary in fusibility according to their composition, 
and the choice should be determined by the nature of 



6 SOLDERING, BRAZING AND WELDING 

the work and the properties of the metal to be soldered. 
Should a solder be used of too high a melting-point, the 
metal will itself be fused before the solder begins to 
flow. 

A point to be particularly observed is that the intro- 
duction of a foreign substance into the solder— for 
example, the addition of a little zinc to a pot of "very 
fine " solder — will utterly spoil it and render it un- 
workable. To remove zinc from solder, melt the 
solder in a pot, take it off the fire and stir in powdered 
sulphur or brimstone until the whole is of the con- 
sistency of wet sand. Replace the pot on the fire and 
melt, but do not stir the contents. The sulphur and 
zinc will rise to the surface and form into a cake. 
Now take the pot off the fire and carefully remove the 
cake without breaking by employing two pieces of 
hoop iron with bent ends. 

It is false economy to use a rough solder for fine 
work on the score of cheapness, since more solder is 
required for a given job on account of the rough 
particles of solder clinging to the work ; moreover, the 
rough appearance of the soldering may completely spoil 
the job. 

The table on the opposite page gives the fluxes and 
the compositions of soft solders suited to a number of 
different metals. 

Making Solder Strips, Wire, Tears, etc.— Only 
clean, pure tin and pure lead should be employed. 
The lead is first melted and then the tin added. When 
all is melted, place a piece of resin on the molten 



SOFT SOLDERS 



Soft Solders for Various Metals 









Soft 


Solder 


Metal to be 


Flux 








soldered 












Tin 


Lead 


Other con- 
stituents 


Aluminium 


stearin 


see 


table 


on p, 59 


Brass . . r 
Gunmetal . 
Copper . I 


* zinc chloride, resin < 
or ammoniuinJ 


66 


34 




63 


37 




chloride . . . 1 


60 


40 




Lead 


tallow or resin 


33 


67 




Block tin 


zinc chloride . 


99 


1 




Tinplate 


zinc chloride or 










resin 


64 


36 




Galvanised 










steel . 


hydrochloric acid . 


58 


42 




Zinc 


hydrochloric acid . 


55 


45 




Pewter. 


gallipoli oil 


25 


25 


bismuth, 50 


Iron and 










steel . 


ammonium chloride 


50 


50 




Britannia 










metal 


tallow or resin 


25 


25 


bismuth, 50 


Gold . 


zinc chloride . 


67 


33 




Silver . 


zinc chloride . 


67 


33 




Bismuth 


zinc chloride . 


33 


33 


bismuth, 34 



* Zinc chloride is the ordinary "killed spirits." 

metal to act as a flux, and after well stirring, the solder 
is made into strips by pouring from a ladle. Solder 
should not be poured into sand. It may be poured 
into strips on an oiled sheet of black iron, preferably 
corrugated to accommodate the strips. In the absence 
of a corrugated iron sheet, some workers use a ladle 
resembling a large spoon with a hole about ^ in. in 
diameter near the end. To form the strips, get a 
ladle full of solder, place it on a flat iron sheet; then, 
tilting the ladle to allow the solder to flow over the 
hoe, quickly draw the ladle across the sheet. A thin 



8 SOLDERING, BRAZING AND WELDING 

strip of solder should thus be formed, and the thick- 
ness of the strip may be varied by increasing or 
decreasing the diameter of the hole in the ladle. A 
button of solder usually forms at one or both ends of 
the strip, and this excess should be melted off the 
strips by just dipping the ends into the molten solder 
in the pot. 

Solder wire is very handy for small work, and can 
be made in the following way : Roll a sheet of stiff 
writing or drawing paper into a conical form, rather 
broad in comparison with its length ; make a ring of 
stiff wire to hold it in, attaching a suitable handle to 
the ring. The point of the cone should first of all be 
cut off to leave an orifice of the size required. It 
should then be filled with molten solder, and held above 
a pail of cold water, and the stream of solder flowing 
from the cone will solidify as it runs and form the wire. 
If held a little higher, so that the stream of solder 
breaks into drops before striking the water, it will 
form handy elongated "tears" of metal; when it is 
held still higher, each drop forms a thin concave cup 
or shell, and each of these forms will be found to have 
its own peculiar uses in blowpipe work. 

The method adopted for granulating tinman's 
solder, which is very rarely called for, is as follows : 
Place a piece of wood, well greased, over a tub con- 
taining water, and by gently pouring the molten alloy 
from a distance in a small stream on to the greased 
board, the metal is broken up into a large number of 
very fine shots, which run off the board into the water 



SOFT SOLDERS 



and are immediately cooled. The fine shots are then 
taken from the water and gently dried. 

Making Solder from Pewter. — This alloy is com- 
posed of variable proportions of tin and lead, the 
average composition being about 4 parts of lead to 
1 part of tin. If old pewter is to be utilised for 
making solder, tin will have to be added to the molten 
pewter. Thus, to convert 5 lb. of average pewter to 
" coarse " or "common " solder, add 1 lb. of tin; to 
"fine " or "medium," add 3 lb. of tin; and to "very 
fine " or "best," add 7 lb. of tin. The respective pro- 
portions of lead and tin will then be '2 and 1 ; 1 and 1 ; 
and 1 and *2. After the proper quantity of tin has been 
added, mix some powdered sal-ammoniac with the 
molten metals, and well stir the alloy; it is then ready 
for pouring into the moulds. 

Making Coarse Solder from Composition Piping. — 
Good composition piping is made of nearly all tin, or 
an alloy of tin and lead, in which the former metal is 
in excess, and formerly was much used by plumbers 
in the making of coarse solder, as the material consisted 
of odd pieces of small value. As, however, a great 
deal of composition tubing is made out of old metals 
of which lead, tin, antimony, arsenic, and zinc form 
the alloy, it is not advisable to introduce it into solder. 
Should it be done, the melting point of the solder would 
be raised, and in applying it to the lead to be joined 
together, would probably partly melt it. Neither do 
the metals named alloy in a thorough manner, but 
partake more of the nature of a mixture in which the 



io SOLDERING, BRAZING AND WELDING 

constituents partly separate when making the joints, 
and some, especially zinc, show as small bright lumps 
on the surface. Joints wiped with what is usually 
called ''poisoned metal "are difficult to make, almost 
invariably leak when on water service pipes, and are 
dirty grey, instead of bright and clean. The zinc 
could be removed from the mixture by the method 
already given. 

Combined Solder and Flux.— This consisted of 
equal parts of lead and tin made into fine tubing and 
afterwards filled with flux having resin as a base. 
"Thiol" is a paste made of finely powdered solder and 
a special flux, and there is also "Thiol wire " having 
a core of flux. 

A "magic " solder, sold by hawkers, consists of the 
above tubular flux-filled solder of such low melting 
point that it can be fused in the flame of a lighted 
match. 

Soft Solders that Melt in Boiling Water.— The 
following soft solders melt at a temperature lower than 
that of boiling water: 1 part tin, 1 part lead, and 2 
parts bismuth, melting point about 200° F. ; 8 parts 
lead, 4 parts tin, 15 parts bismuth, and 3 parts 
cadmium, melting point 140° to 150° F. ; 6 parts lead, 
7 parts bismuth, and 1 part cadmium, melting point 
about 180° F. To ensure the alloys melting at the 
temperatures stated, the metals of which they are 
formed should be free from impurities, and care should 
be taken to prevent oxidation while making the alloys. 
When melting the metals, that having the highest 



SOFT SOLDERS n 

melting point should be melted first, with a layer of 
resin over it, the other metals being added in the order 
of their melting points. The alloy should then be well 
stirred with a wooden stick, and poured quickly into 
moulds. 

Re-melting and Overheating Solder. — After solder 
has been re-melted a number of times or has been 
overheated, its content of tin will be reduced, and the 
solder will become poorer and coarser. The tin melts 
earlier than the lead and, being the lighter of the two, 
floats over it, and is thus fully exposed to the air, the 
oxidising effect of which on heated, molten metal is 
extremely active. The oxidised tin forms a dross, from 
which most of the tin may, however, be recovered by 
melting it with powdered charcoal, which combines 
with the oxygen and frees the tin. The addition of a 
little fresh tin is desirable. 



CHAPTER III 
Fluxes Used in Soft-soldering 

Why a Flux is Required.— The great essential to 
successful soldering is the chemical cleanliness of the 
surfaces to be united, and the proper use of a flux. 
Although work may be filed or scraped perfectly bright 
and clean, this is not the kind of cleanliness which is 
alone sufficient ; there is always in course of formation 
a film of oxide present, and the duty of the flux is to 
dissolve this and keep any more from forming. Then, 
and not until then, will the molten solder "run " and 
spread over faces in the intimate contact necessary. If 
this vital precaution of cleaning and fluxing is always 
observed, the difficulties which many beginners ex- 
perience in effective soldering will vanish. 

Variety of Fluxes. — There are a good many fluxes 
employed, including tallow T (largely used for lead and 
pewter), resin (used for lead, compo-pipe, and tinned 
metals), hydrochloric acid, diluted (for zinc and 
galvanised iron), and chloride of zinc (the well-know T n 
"killed spirit ")• The last-named is the most generally 
used, being suitable for tinplate, tinned iron, new 
zinc, copper, and brass. Sal-ammoniac is also utilised, 
sometimes in conjunction with chloride of zinc. The 
small worker who does but a moderate amount of 
soldering will find it convenient to use a soldering 



FLUXES USED IN SOFT-SOLDERING 13 

paste such as "Fluxite," which is sold in a tin, and 
can be kept handy and applied to the work with a 
sliver of wood. " Tinol " is a paste flux in combination 
with a solder. 

Preparing Zinc Chloride ("Killed Spirit ").— Make 
this flux at home from finely snipped new sheet-zinc 
and pure hydrochloric or muriatic acid. (This is suffi- 
ciently cheap at any working druggist's stores, and 
infinitely preferable to the contaminated oil-shop 
quality known as "spirits of salt.") Stand the acid 
outdoors in a stoneware crock, add the zinc cuttings 
a few T at a time at first, and when the first violent 
ebullition moderates, put in the rest. Be sure to pro- 
vide an excess of metallic zinc, observing that a 
quantity remains undissolved after all chemical action 
ceases. Leave the metal in the liquor for twelve hours 
(covering the crock with a pane of glass), then decant 
and filter into a wide-mouth glass jar of handy size. 
Do not add water to the concentrated sine chloride 
solution; dilution is sometimes recommended, but 
should never be done; the heavy, slightly syrupy, 
water-bright liquor should be used as it is. The 
alleged "cleaning' 1 qualities of this chloride can 
scarcely be admitted to exist, and its principal function 
is to shield the surfaces of the work from oxidation ; 
this it fulfils by the formation of a viscid glaze on the 
heated metal when the salt reaches its anhydrous 
(waterless) condition by evaporation. The addition of 
water to the flux, therefore, only uselessly prolongs 
the period occupied by evaporation, and wastes heat. 



i4 SOLDERING, BRAZING AND WELDING 

Always remove all trace of flux from finished work, 
first by soaking in water, and afterwards by washing 
with soda, soap, and water. Otherwise, there is the 
risk of the work being corroded. 

Special "soldering solutions," obtainable ready pre- 
pared, should not be used in preference to zinc chloride 
made as before explained or to the well-known paste 
fluxes. 

Applying the Flux. — A short heavy bottle about 
3 in. or 4 in. high is best for bench use as a flux con- 
tainer. It should be particularly noted that soldering 
and soldering tackle should be kept as far away from 
other work (and iron and steel goods and tools) as 
possible. 

A pointed wooden stick is not a good tool for 
applying killed spirit, because the acid acts on the 
wood, which becomes unpleasant to handle, and the 
liquid does not leave the wood readily enough to place 
the right quantity on the exact spot to be soldered. A 
galvanised iron wire is better. Another good tool is a 
thin steel or iron "spit," about 12 in. long, and a steel 
knitting-needle is also excellent. Should a brush be 
preferred, take a few hairs from a broom, place them 
in one end of a thin metal tube, and then flatten the 
end with a blow from a hammer. 

A brush made by hammering the ends of a short 
length of cane until the fibres are like bristles is fre- 
quently used for the purpose, the handle end being 
soaked in molten wax before using the cane brush the 
first time. 



FLUXES USED IN SOFT-SOLDERING 15 

A convenient method of applying liquid flux is to 
have a bottle with a screw cap sprinkling top such as 
is often used for perfumes, and to push a length of 
thick galvanised iron wire through the orifice in the 
stopper, leaving about 1J in. projecting above. The 
lower end should just reach the bottom of the bottle, 
and may be flattened and pointed. The lead nipple is 
squeezed round the wire to hold it firmly, and the pro- 
jecting end bent into a ring to form a handle, as shown 
in Fig. 1. The cork part should be thinned a little to 
render it an easy fit in the bottle neck. The flux can 
be quickly applied with the wire exactly where it is 




Fig. 1. — Wire for Applying Flux 

wanted, and in very small quantity; for a long seam 
the wire can be run along with one dip in the solution. 
The fingers need not be brought into contact with the 
flux ; the cork will not go soft and will not sink down 
owing to the lead flange supporting it. 

Flux Used on Food Containers. — Killed spirits is 
objectionable as a flux for soldering vessels intended to 
contain food of any kind. Not only is this flux a 
poison, but it is liable to produce subsequent rusting 
wherever used unless all traces of it are thoroughly 
removed immediately after soldering. A good non- 
poisonous flux suitable for tin boxes may be made by 
dissolving resin in oil. Place a quantity of powdered 
resin in an iron vessel, add colza, olive, or any similar 



i6 



SOLDERING, BRAZING AND WELDING 



oil, and apply gentle heat, meanwhile stirring it until 
the resin is dissolved. Dissolve as much resin m the 
oil as possible without making the flux too thick (when 
cold) to apply with a brush. One or two small experi- 
ments will soon decide the required proportions. The 
resin is really the base of the flux ; but the oil is added 
to facilitate its application and removal before and after 
the soldering process. 



CHAPTEE IV 
Soft-soldering with the Copper Bit 

Choice between Blowpipe and Bit. — The method 
of heating depends on the size of the work, or rather 
the area to be soldered, and the conveniences at the 
command of the worker. The soldering bit, although 
so commonly used, is not necessarily the best for 
the beginner to use for small work. A blowpipe flame 
— from a bunsen burner or a spirit lamp — is far more 
convenient and neat, and its effects can be applied and 
localised with the greatest precision, down to the 
merest pin point of heat applied at a definite spot. 
The bit is chiefly useful for long joints such as in tin- 
plate work, and for pieces bound together to which the 
bit is applied to heat up and melt solder between them. 
But for work where the soldering area does not measure 
more than an inch or so (and there is a vast amount 
of this kind), the blowpipe flame is far preferable. It 
must be admitted, though, that this is a matter in 
which some workmen might have two distinct 
opinions; and, as already remarked, the bit is far more 
commonly used. 

Copper Bits.— The soldering bit or bolt (miscalled 
an "iron ") carries a pointed lump of copper at the 
(Mid (Fig. 2), riveted in, or alternatively, in small 
sizes, screwed on to the shank. Some bits are pivoted 

c 17 



18 SOLDERING, BRAZING AND WELDING 

(see Fig. 3) to enable them to point at various angles 
for dealing with difficult situations. 

A home-made bit (Figs. 4 and 5) may be made by 
drilling and tapping a short length of lj-in. or 2-in. 
square copper to receive the screwed end of a rod of 
TO-in. iron, the copper being afterwards heated and 
drawn to a point or to a blunt edge as preferred. This 



Fig. 2. -Soldering Bit 




Fig. 3.— Pivoted Soldering Bit 



forms a good bit for most ordinary purposes. An 
axe-head or hatchet bit is shown in Fig. 6 ; the copper 
bolt is riveted in the eye of the iron rod, the bit, how- 
ever, being free to revolve, as this is essential when 
making joints in heavy lead pipe, for which purpose it 
is principally used. Fig. 5 represents a bit which is a 
combination and modification of the tw T o others, and 
it is largely used for the internal soldering of bottoms 
of large drums, milk churns, etc., where great local 
heat is required. 

As to the size of bit required, for ordinary small 



COPPER-BIT SOLDERING 



*9 



work the straight type should not be less than 8 oz. or 
10 oz. (weight of the actual copper). 

Two bits are very useful in doing a large job, 
as the work can then be arranged to progress 
continuously, one bit heating while the other is 
in use. 

A bit suitable for quite light work can be easily 
made by drilling and tapping a piece of copper, say 



¥'if. 4. — Home-made Soldering Bit 



'■■■ ." 



iir~^ 



Fig. 5. — Bit for Internal Soldering, etc. 



Fig. 6.— Hatchet Soldering Bit 



I in. by J in. by 1J in. long, either in the end or in the 
side, for a fV-in. steel rod 12 in. long, a handle being- 
then fitted at the other end. 

In the "Tinol" telescopic soldering bit for 
amateurs' use, the handle is in three parts : (a) the 
actual wooden handle bushed with metal, and provided 
with a set-screw shaped like a screw eye, and therefore 
easily turned ; (J?) a steel tube which telescopes into 
the first part, and which is also provided with a set- 
screw ; and (c) a. short rod, having at one end a 



20 SOLDERING, BRAZING AND WELDING 



hatchet-shaped copper bit. The extreme length of the 
tool is 12 in., and the length, when the parts are 
telescoped together, is about 5 in. 

The "Fluxite " bit is larger and heavier. It has a 
hollow cast-iron handle, perforated to dissipate the 
heat, threaded internally at one end to receive the 
screwed end of the iron stem, only 5 in. or so in 
length, which at the other end screws into an adapter 
or holder which, in turn, receives the screwed end of 




Fig. 7.— Spirit-heated Bit 

the copper bolt, itself about 4 in. long. The bit is 
taken to pieces in a few moments, and is quite a work- 
manlike tool. 

Spirit - heated Soldering Bits.— Bits heated by 
benzoline or spirit may be made with a small barrel- 
shaped reservoir which also forms the handle. One 
end of the reservoir is fitted with a filling cap, and 
from the opposite end protrudes the tube carrying the 
burner. To the tube end of the reservoir an iron clip 
is attached, and this secures an iron bar which stands 
out over the burner head. At the end of this bar the 
copper bit is attached and held either vertically or 



COPPER-BIT SOLDERING 



21 



horizontally in the flame. Tool merchants' catalogues 
show a variety of such implements. Fig. 7 illustrates 
one of the most elaborate of them all, the weight com- 
plete being 2 J lb. It has a polished brass container a, 
of J pint capacity — sufficient for 45 to 60 minutes, 
whence the benzohne flows to the burner b, the flame 
from which heats the copper bit c. This bit may be 
of any of the regular shapes, and weighs about J lb. 
The position shown is that for heating the bit pre- 





Fig. 8. — Bit attached to 
Blow-lamp 



Fig. 9. — Gas-heated Bit 



paratory to soldering. The tray d catches any drips 
that might occur at starting, e is the stand, F the filler 
cap, G is the regulating handle, and H is the clamp that 
holds the bit in place. 

A writer in Popular Mechanics has stated that 
the ordinary blow-lamp, with the burner end equipped 
with a copper bolt (see Fig. 8), makes an excellent 
soldering device. The point can be easily kept at the 
proper heat, and there will be no w^ant for hot coppers. 
The end of the burner is threaded on the outside, and 
a hole is drilled in the copper point and threaded to 
match. Small holes are drilled in the copper in the 
same manner as in the burner, to make vents for the 
flame. 



22 SOLDERING, BRAZING AND WELDING 

Gas-heated Bits. — These are largely used in factories, 
and are cleanly, expeditious, safe, and convenient. 
The type shown by Fig. 9 is very handy, and the 
illustration and description are due to F. X. Sommers, 
Jun., in the American Machinist. A mixture of air 
and gas enters the pipe at about 10 lb. pressure, or 
enough to give a hot, blue flame. The part A is of 
cast-iron, which, on experiment, has been found to 
last longer without corroding than steel, although 
copper would be better. The soldering bolt b was 
made of steel because it kept the correct shape point 
much longer than cast-iron or copper, although the 
latter metal is better for transmitting the heat. 
The point should be tinned before using. This 
form of soldering head is being used on automatic can- 
soldering machines, and does the work effectively. It 
also saves gas. It will heat to the correct temperature 
in about 1J minutes. 

A gas-heated bit invented by W. G. Eyan is shown 
in Figs* 10 to 13. The actual bit a is held in a steel 
sheath B having a space underneath the bit to allow 
the gas to pass. The sheath has a row of holes on 
each side to allow the gas to come through, the flame 
enveloping the bit when in use. The gas, -supplied 
through a flexible tube, passes through the tube that 
forms the handle, at the end of which is a small 
chamber c to admit air, which mixes wdth the gas to 
cause it to burn atmospherically, the supply of gas 
passing through a small cone valve d and thence 
through the air chamber. In the air-inlet holes e at 



COPPER-BIT SOLDERING 



23 



the end of the air' chamber are fitted small cones F to 
regulate the quantity of air. All the cones, including 
the gas-valve cone, are connected rigidly together, so 
that when cutting down the gas supply temporarily, 




Fig. 10. — Gas-heated Bit complete 




C F 




Fig. 11.— Air Inlets 
in End of Air 
Chamber 



Fig. 12. — Section through Air 
ChambeY and Gas-reducing 
Valve 




Fig. 13. — Details of Cones or Needles 



the air supply is automatically reduced, and the gas 
flame remains in being, although its size is much 
reduced. It has been found that, in some gas-heated 
bits, the cutting down of the gas seriously interferes 
with the proportion of the gas and air mixture, result- 



24 SOLDERING, BRAZING AND WELDING 

ing in a back-fire. The device here described has been 
invented especially to obviate that trouble. To reduce 
the gas supply and, with it, the air supply also, all that 
is necessary is a slight forward movement of the fitting 
to which the cones or needles are attached. The 
copper bit is kept in position by the sheath or clip, the 
small bolt in which can be taken out in a moment when 
special attention to the bit becomes necessary. The 




Fig. 14. — Gas-stove for Heating Bits 



connection to the flexible gas tubing is at G, while h 
indicates a guide and stuffing box for the gas-valve cone 
or needle. 

Stoyes for Heating Soldering Bits. — Although a 
copper bit may be heated in any fire, it is better to 
avoid the dirt, smoke and tarry stickiness which are 
often present in a coal fire. In the absence of gas, 
a bright, clear coke fire or a charcoal fire should be 
used whenever available. Portable oil stoves of the 
wickless type can also be employed, but the ideal fuel 
is g^s, which may be regulated at will to give a 



COPPER-BIT SOLDERING 



25 



uniform temperature. Two gas r stoves specially con- 
structed for copper bits are shown by Figs. 14 and 15. 

Tinning a Bit. — Before a bit can be used, it must 
be "tinned," that is, coated with solder in a smooth 
complete covering, for which purpose — by one method, 
not the best, but the most general — the end is heated 
to a dull red, rubbed quickly with the file on the facets, 
dipped in killed spirit or "fluxite," or rubbed against 
a piece of sal-ammoniac, and then applied to a stick qr 




Fig. 15. — Gas-stove for Heating Bits 

lump of solder, the facets being quickly wiped or 
rubbed on a piece of tinplate so as to spread the solder 
evenly. When properly done, the nose of the bit is 
coated with a smooth film of solder. This must 
always remain so, or the bit will not act, and when it 
is honeycombed, or the "tinning '" is present in 
patches, it must be re-tinned. A bit must never be 
raised to a red heat sufficient to melt the tinning. The 
bit does not operate well at such a heat, because its 
contact makes solder too fluid and apt to run too 
quickly. 



26 SOLDERING, BRAZING AND WELDING 

When dipping a hot bit, prepared for tinning, into 
killed spirit, a sharp pop, without smoke or splutter- 
ing, denotes the right temperature. If, on with- 
drawing the bit, it is damp and still unclean, it had 
not been heated sufficiently. 

Another method of tinning may be mentioned. 
Into a small and clean tin box (a 2-oz. tobacco tin 
about f in. deep) put some scraps of solder and 
powdered resin. Heat the bit to a very dull red, 
quickly file up clean on one side of the point, and then 
plunge into the solder and resin and rub about ; it will 
at once take on a coat of the alloy. A second side of 
the bit may be tinned by then repeating the opera- 
tion, re-heating if necessary. The bottom of the box 
should be covered with solder, which adheres easily 
enough, with a film of resin on top. It is probably 
most convenient to tin the under side and the left- 
hand working face of the bit. "Tinol " could be used 
in this way without admixture with anything. 

Still another method is to use a firebrick having a 
hollow in which the solder and resin are placed ; but 
the tin box plan is thought to be better. 

Undoubtedly the best method of tinning a bit is 
that in use by the plumber who well knows the 
invaluable qualities of sal-ammoniac (ammonium 
chloride) for the purpose. He has no wish to squander 
energy on those vigorous rubbings of the bit — on 
paving-stone, bath brick, tinplate, etc. etc., and he 
believes that the habit of dipping the bit into zinc 
chloride is both slovenly and wasteful, for not only is 



COPPER-BIT SOLDERING 



27 



this corrosive stuff sprayed about broadcast, but the 
remainder is soon rendered unfit for its purpose by con- 
tamination with copper chloride and dirt from the fire. 
The outlay of a few halfpence on a sizable slab of sal- 
ammoniac will keep the bit in the best condition for 
years, and save hours of superfluous labour. Com- 
mercial sal-ammoniac is obtainable in large, rugged 
crystals of a tough, fibrous texture. A piece weighing 
upwards of J lb. can be trimmed to a roughly rect- 




Vl l l , l , l , l , l I'l'l 1 ! 1 
.ID. »l|l| 1 , I 1 



Fig. 16. — Tinning Bit in Sal-ammoniac Block 



angular slab, a few inches long and wide and about 
1 in. thick ; and a cavity should be scooped in one of the 
flat sides to accommodate the bit. 

Let the bit-faces be made shapely and filed bright 
and the tool thoroughly heated in a clean fire, 
removed, flicked free of ash, and then held down firmly 
in the cavity of the sal-ammoniac block (see Fig. 16). 
Profuse white fumes will arise, and the surface of the 
salt will fuse. Bear heavily on each facet in turn, and 
then melt a few beads of solder into the cavity along 
with the bit, and the latter will become brightly tinned 



28 SOLDERING, BRAZING AND WELDING 

m a moment or. so. The bit should be applied to the 
"ammonia block " every few heats, or as required, as 
the work progresses, and flicked with a tuft of 
dampened cotton- waste. 

The sal-ammoniac has one great disadvantage; — it 
is deliquescent (collecting moisture from a damp 
atmosphere), and its near proximity to most metals 
oxidises and corrodes them. Iron and steel, particu- 
larly, it rusts rapidly and deeply. Therefore the tools 
(saw and chisel) used to shape the block must be 
washed, dried, warmed, and greased before they are 
laid by, and the waste fragments must be carefully 
swept up and disposed of. The block itself must 
always be kept apart from tools. Plumbers enclose it 
in a sheet-lead box wrapped in a greasy rag ; amateurs 
may store it on a dry shelf, parcelled in waxed paper 
secured by a rubber band, or in a length of motor-tyre 
inner tube, rolled up. 

Simple Soldering. — Scrupulous cleanliness in every- 
thing connected with the process of soldering is 
essential to success. The ordinary procedure in 
making a joint is to clean the surfaces first by filing 
or scraping with a scraper or a knife or a plumber's 
shave-hook (Fig. 17). In some cases, dirty metal is 
cleansed with dilute hydrochloric acid. With or with- 
out preliminary heating of the work, flux is then 
applied to the joint, and the heated bit is held in one 
hand and a stick of solder in the other, and the stick 
drawn along the joint while the bit touches it (or 
"drops " of solder may be transferred to the work by 



COPPER-BIT SOLDERING 29 

means of the bit). This will cause a line of molten 
solder to run, and some skill and care are necessary to 
get just the right amount of solder without wasting it 
and allowing it to spread in a lumpy fashion beyond 
the necessary area. The bit is next worked up and 
down the joint to spread the solder, and by the trans- 
mitted heat to make it thoroughly penetrate the joint. 
This is an outline of the process, and there is a number 
of points requiring special instruction or a few words 
of caution. 

Note that the work must be filed, scraped, or other- 




Fip. 17. — Shave-hook 



wise mechanically cleaned, and then chemically cleaned 
by coating with the flux just where the soldering is 
required. In heating the copper bit do not let it reach 
even a dull red heat. Lightly dip it into the flux to 
clean the point; then, with a small button or blob of 
solder resting on the work, place the bit momentarily 
upon it to cause the solder to flow, and draw the bit 
where the solder is required. 

Many beginners try to draw along the solder with 
an insufficiently heated bit. The result is a series of 
lumps — " putting it on with a trowel," as it is some- 
times termed. A good joint cannot be made this way, 
however much solder may be used. 



30 SOLDERING, BRAZING AND WELDING 

Some beginners fly -to the other extreme, and try 
to make a neat job with a red-hot bit, which results in 
the solder assuming a sandy appearance and in the 
work being discoloured. 

Others try to solder uphill — that is, they hold or 
place the work in such a way as to cause the solder to 
flow away from where it is required. The correct 
method is to solder downhill by tilting or inclining the 
work, so that the solder will always collect around and 
travel with the point of the bit. This, besides facili- 
tating the work, makes a strong joint, and imparts a 
clean and neat appearance to the job. 

A common mistake is to hold the bit in a cramped 
and awkward way, as in Fig. 18, the hand being 
twisted under the handle, the thumb being brought to 
the top, and the elbow forced to the side. TKe correct 
positions of arm and fingers are shown in Fig. 19 ; the 
elbow is held well out from the body, and the thumb 
is placed directly under the handle of the bit, forming 
a fulcrum over which the bit may be slightly raised or 
depressed at will. This is all-important when solder- 
ing very fusible metals such as pewter, tin, etc., on 
which the weight of the copper bit should never be 
allowed to rest, as otherwise a hole will suddenly be 
made in the work. The whole weight of the bit should 
be supported and balanced on the thumb by the down- 
ward pressure of that part of the hand close to the little 
finger. The worker should not for a moment lose 
control of the copper bit, and control is always assured 
when the thumb is underneath the handle. 



COPPER-BIT SOLDERING 



3i 



There is but little strength in a butt joint with the 
edges of the metal only just touching — that is, without 
a lap ; to take the example of a small cylinder, the body 
seam should have at least a J-in. lap. Fig. 20 repre- 
sents an example of internal grooved seam soldering, 
which may be executed in the following way: — After 
applying the flux, place a small button of solder in- 




Figs. 18 and 19. — Incorrect and Correct Methods of Holding Bit 

side the cylinder on the seam, rest the bit momentarily 
on the solder to melt it, and then draw it gently along 
the seam. The cylinder should be slightly tilted to 
allow of the solder travelling with the point of the bit. 
The hand should avoid touching any part of the work 
that comes directly into contact witli the copper bit, as 
otherwise the hand would be badly burned. 

The method of internally soldering the bottom on a 
canister, etc., is shown in Fig. 21. The bottom is 



32 SOLDERING, BRAZING AND WELDING 



held in position by gently pressing it against (but not 
placing it on) the bench during the soldering process, 
while the tilt of the canister and the position of the bit 
cause the solder to travel with the bit. 

In soldering all such articles, the soldering should 
be done with one sweep of the bit, the left hand mean- 
while making the necessary revolution. This saves 




20. — Soldering Internal 
Grooved Seam 



Fig. 21.— Soldering on Can 
Bottom Internally 



time and solder, and avoids the unsightly appearance 
of a series of starts and stops. 

In work of a larger and more substantial nature, 
as, for example, galvanised or tinned iron work, the 
bottom of the article is first "knocked up," and then 
soldered internally. Fig. 21 represents an example 
of internal soldering where the whole weight of the bit 
is shown resting on the molten solder inside ; this pro- 
vides the local heat required to "sweat " the solder into 



COPPER-BIT SOLDERING 



33 



the four thicknesses of metal which constitute the 
bottom seam; and for this work the bottoming bit 
shown in Fig. 3 is often used. Pewter, lead, zinc and 
tin — the latter should not be confused with tinplate 
— do not require sweating, on account of their 
low fusibility, and any attempt even to solder them 
with a very hot bit will probably end disastrously. 

Fig. 22 shows an 
example of external 
seam soldering . The 
method there shown is 
invariably adopted for 
simple lap seams, al- 
though grooved seams 
are similarly soldered. 
A grooved seam, however, 
should preferably be 
soldered internally. The 
position of the worker's 
elbow and thumb should 
be noted, as should also 
the tilt of the cylinder (more pronounced in this case 
than the other) in order to secure the downflow of 
the solder. 

Sweating has already been mentioned. It should 
be said that one of the easiest ways in which a 
beginner may make a reliable joint is to prepare both 
faces of the joint by fluxing and covering with a thin 
film of solder, and then pressing the two parts together 
with the hot bit until the top part " floats " and then 




Fig. 22.— Soldering Can 
Externally 



34 SOLDERING, BRAZING AND WELDING 

settles down. The advantage of this way is that one 
can be sure of perfect application of the solder to the 
joint faces, since each is dealt with first and thoroughly 
coated, with no faulty patches. Sweating is also done 
in the flame of a bunsen burner or blowpipe, as ex- 
plained later. 

Reinforced and Filled -in Soldered Joints.— The 
bottoms of square or cylindrical vessels should, prefer- 
ably, be soldered from the inside, and ''buttons " of 
solder may be melted to assume a stout triangular- 
shape stud in the corners of the square vessels. A 
tinned rivet is sometimes riveted or just placed in a 
corner, and sufficient solder floated over it to strengthen 
the corner. Solder is always liable to run through an 
improperly closed seam at the corner when external 
soldering is resorted to ; but in cases where this is the 
only practical method, a tinned rivet may be inserted 
from the outside, and then soldered over. It some- 
times happens that two "raw " edges require soldering 
together without a lap. Where a strong joint is 
required a good plan is to place a length of tinned wire 
over both edges and solder the lot together. In 
addition to strengthening the joint, t1c\e wire consider- 
ably improves the general appearance. A simpler 
joint may be made by "skimming " the solder over 
with a copper bit heated only just sufficiently to melt 
the solder. The quick and skilful touch is required 
to perform this operation satisfactorily ; but a little 
practice will soon bring the necessary proficiency. 
The idea is to "draw" the solder across the joint 



COPPER-BIT SOLDERING 35 

quickly, before it has time to run through. This 
method is useful when soldering thin metal goods of a 
lower degree of fusibility than that of the solder 
employed. No preparation for filling cracks previous 
to soldering can be recommended, beyond such small 
pieces of metal that may be afterwards soldered over 
and effectively hidden. It is much better to endeavour 
to produce work of such quality that this expedient is 
altogether unnecessary. 

Soldering Heavy Milk Churns. — When soldering 
the bottom rims on large milk churns, sufficient heat 
cannot be maintained with only one soldering bit. At 
least two heavy bits are required, so that one may be 
getting hot while the other is in use. The rims are 
usually tinned before being fixed by first pickling them 
in dilute hydrochloric acid, washing, and then dipping 
in a bath of molten tin. When repairing and re- 
soldering the rims, remove all dirt and rust with a file, 
use a few brushfuls of raw spirits further to assist the 
cleaning process, then wash with clean water and 
solder in the usual way, using killed spirits as a flux. 

Soldering Hole in Enamelled Ware.— First scrape 
or file away the enamel quite clear all round the hole, 
apply a little raw spirit to the surface of the iron, and 
coat it with solder in the usual manner. Then cut out 
a tin disc large enough to cover the hole, and solder 
this in, using killed spirit as the flux. 

Soldering Leaded Lights.— For soldering the calmes 
of a lead-light window, the calmes having been fitted 
properly together, shave a small round dot at the point 



36 SOLDERING, BRAZING AND WELDING 

of junction, sprinkle a little powdered resin on the 
shaving, and with a copper bit or with a glazier's iron 
having a tinned face, melt a small piece of tinman's 
ordinary solder on the shaved part so that it tins to the 
lead and forms a round button. 

Soldering Catch on Gun-barrel. — In soldering a 
catch on a gun barrel it will first be necessary to tin 
both barrel and catch, and then to wire them together, 
in addition binding the barrels for some distance from 
each side of the catch, making the ribs secure with 
wedges. To melt the solder, use heaters ; these are 
generally made of copper with iron handles ; or iron 
rods can be used, the ends being made red hot and 
inserted in the barrels. Cut some small slips of thin 
solder and place them on each side of the catch, using 
powdered resin. As soon as the solder melts, remove 
the heaters and cool the barrels. 



CHAPTEE V 

Soft-soldering with Blowpipe or Bunsen Burner 

The Mouth Blowpipe. — Although soft-soldering is 
usually associated with the use of a copper bit, quite 
a number of jobs can be done without one, using 
instead a bunsen burner or, more generally, a mouth 
blowpipe, which is an inexpensive appliance, useful for 
both hard and soft soldering, and with either gas, 



Fig. 24 



Fig. 25 



Fig.2J 



Fig. 23.— Mouth Blowpipe 

Fig. 24.— Black's Mouth Blowpipe 

Fig. 25. — Fletcher's Mouth Blowpipe 



37 



38 SOLDERING, BRAZING AND WELDING 

candle, or a methylated-spirit flame. Three shapes 
of mouth blowpipe are shown in Figs. 23 to 25. In a 
blowpipe flame there are three cones, X, Y, Z (Fig. 
26). X is a non-luminous cone, consisting of a 
mixture of atmospheric air and unburnt combustible 
gases (each with a low temperature) ; Y is a luminous 
cone, composed of burning gases (carbon and carbonic 
acid being in excess) ; and Z is a cone the oxygen in 
which renders it less luminous and free from corn- 




Fig. 26. — Section through Blowpipe Flame 

bustible materials, its temperature being exceptionally 
high, especially where the cone comes in contact with 
the point of the cone Y. Because of its properties ; Z 
is termed the oxidising or outer flame, whilst Y is 
known as the inner or reducing flame, because when it 
is applied to some easily reducible substance — say, lead 
oxide — the oxygen in the substance heated mingles 
with the unburnt carbon in the cone of the flame and 
produces carbonic oxide, the lead being thus separated 
or reduced. The blowpipe flame is one of intense 
heat, even that produced by blowing a common candle 
being capable of melting metallic fragments when they 



BLOWPIPE SOLDERING 



39 



are supported on a bed of charcoal. The pointed flame 
gives the greatest heat, and this can be produced 
simply by increasing or decreasing the space between 
the flame and the article to be soldered or the metal 
to be melted. 

The particular advantage of a blowpipe is that it 
gives a fierce heat at a very localised area, beyond 
which the solder does not run, and it enables spots to 



<M^ 




Moles 

S& "mcK Tube 



Fig. 27 

Fig. 27. — Home-made 
Spirit-lamp 

Fig. 28.— Another 
Home-made Spirit- 
lamp 




Fit*. 28 



be soldered, or parts to be unsoldered, adjusted and 
re-soldered without allowing heat to stray and cause 
trouble at other places. A useful little addition to the 
ordinary blowpipe is a small washer soldered on near 
the mouth end (see Fig. 23), the object of this being 
to raise this part off the bench and so keep it from con- 
tamination with dirt, filings, etc., which are unpleasant 
to the lips. Sometimes the washer is made elliptical 
and slightly concave to fit the lips, so that it forms a 



40 SOLDERING, BRAZING AND WELDING 

convenient stop or steady when the blowpipe is held 
between the teeth without help from either hand. 

Bunsen Burner, Spirit Lamps, etc. — The bnnsen 
burner is, of course, the most convenient device for 
heating (when the bit is not in question) ; but failing 
a gas supply, a spirit-lamp must be employed. This 
is a small glass bottle with wick, methylated spirit 
being used. Plumbers and gasfitters make use of metal 
tubular lamps fed with spirit poured on cotton-wool, 
and having a blowpipe tube attached and coupled up 
to the lips with a rubber tube ; they also use wax tapers. 

A methylated wick lamp may be easily made out of 
a small "self -opening " canister, as shown in Fig. 27. 
The holes near the top increase the efficiency of the 
flaime. Another spirit smoldering-] amp is shown by 
Fig. 28. The container for the spirit can be made 
about 3 in. in diameter by about 1J in. deep, with a 
handle soldered on. A glance at the illustration will 
explain the burner. An outer wick surrounds a piece 
of tube, which itself contains another wick. The 
spirit in the inner tube is vaporised by the heat from 
the burner when the outside wick is lit. The spirit 
vapour issues from a 3V -in. hole at a. At b a ring 
is slipped over the outer wick, holding it to the central 
tube. By lifting the central tube the height of the 
vaporising flame can be adjusted. The vaporising 
tube is a piece of |-in. brass tube with a f-in. gas cap 
screwed on the end, or a brass disc can be brazed in. 
The total cost should not exceed sixpence. 

Bench Blowpipes.— The best form of gas bracket for 



BLOWPIPE SOLDERING 



4i 



bench use is one having a horizontal swivelling arm, 
and screwed to the bench by a flange, as shown in 
Fig. 29. The swivelling head -is also a cock, which 
shuts off the gas when the jet arm is pushed over at 
right angles to the edge of the bench, as indicated, and 
the gas is connected by an iron or compo pipe under 
the bench. A second gas tap should be arranged in 
the supply to regulate ^,r,on_of bi^m^ 

the amount of gas, 
and for reasons of 
safety. A simple de- 
vice (see Fig. 30) may 
be made by anyone, 
and connected to a 
rubber - pipe connect- 
ing head on the gas 
supplying 
to the bench 
and workshop. 



bracket 



light 




Fig. 29.— Swivelling Gas-burner for 
Bench Soldering 



A design of gas 
blowpipe which 
leaves one hand free is shown by Fig. 31. This 
enables the worker to apply the solder to the work 
(holding the end of a strip against it), after it has 
been brought to the melting heat of the solder. The 
blowpipe is arranged so that it can be held in the hand 
or dropped into a hole in the bench. 

Tapers. — Tapers for a blowpipe flame are made by 
untwisting cotton rope until the threads of the in- 
dividual strands are straight. These are then dipped 



42 SOLDERING, BRAZING AND WELDING 




30. — Simple Bench Burner 



in melted wax made by melting two wax candles over 
a gas stove in a jam jar. They are repeatedly dipped 
until sufficient thickness of wax is obtained. The wax 
should be just sufficiently hot to keep melted. 

Catching-tray for 
B u n s e n Burner. — 
The blowpipe is not 
essential for some 
kinds of work, such 
as when the job can 
be held wholly in 
the flame without 
causing any damage. 
When solder is being 
melted to drop on to 
a surface, the plain 
bunsen or atmo- 
spheric flame is also 
sufficient, though in 
this case it is well to 
tilt the burner over 
so as to prevent the 
solder dropping 
down the tube. An 
elbow fitted on the top of the tube is handy in this 
connection, to deflect the flame at an angle, and Figs. 
32 and 33 show this, with the addition of a tray to 
catch the dripping solder which otherwise would 
splash on the bench and cause untidiness. The tray 
is riveted to a strip of brass bent round to slip over 



3 /i6Tube 



for Rubber 
Connection fa 
Gas 

ConrtecT 

with 
rubber 
rube /b v 
Mouft>fr/ece 




Fig. 31. — Gas Blowpipe for Bench 



44 SOLDERING, BRAZING AND WELDING 

the outside of the elbow, and a small pin riveted into 
the tube prevents the tray from falling down. 

Blow Lamps. — A soldering lamp is used sometimes 
in the place of a blowpipe, and it should combine per- 
fect security with compactness and portability. Tool 
merchants' catalogues show a number of styles. In 
the lamp shown by Fig. 34, benzoline is burnt. When 
the lamp is in use and the body of it is very hot, the 
inside pressure does not exceed three-fifths of an 
atmosphere, whether the regulator K is open or almost 
closed. Thus the danger of explosion, which is such 
a drawback to some of the lamps that use ordinary 
paraffin, is avoided. The upper parts of the lamp are 
subjected to great heat and therefore are packed with 
asbestos, which serves as a filter and stops any im- 
purity in the benzoline from getting to the burner. 
The flame can be lowered to a glimmer when not 
actually in use, thus saving the trouble of relighting. 
When the lamp is to be used, the regulator E is screwed 
up tight; and care must be taken to ascertain, from 
time to time, that the burner or nipple c is open and 
perfectly clean. If this becomes obstructed, it- can be 
cleaned by unscrewing the tube T and passing a fine 
steel wire through the hole. The lamp should be com- 
pletely filled with benzoline every time it is to be used. 
A little methylated spirits is poured into the basin A, 
and set alight. When the apparatus has become 
slightly warm, the regulator is opened gradually. To 
extinguish the flame, the regulator must be screwed up 
tight. If any escape is observed round the screw of 



46 SOLDERING, BRAZING AND WELDING 

the regulator, the square p should be screwed up with 
the key supplied by the makers, so as to tighten the 
asbestos packing. The lamp above described is only 
one of a great number of such appliances, but it is fairly 
typical of them all. The difference between a 
solderer's and a brazer's blowlamp is merely one of 
size and power. 

How to Operate a Mouth Blowpipe.— The opera- 
tion of using the mouth blowpipe does not consist in 
blowing intermittent and strong blasts with the lungs, 
as this would soon exhaust the wind power. For very 
light jobs, however, this method is sometimes adopted ; 
but once the proper way is discovered, the user 
naturally falls into the use of this method. 

The proper way to keep a continuous blast is to 
breathe naturally through the nose, and at the same 
time keep the cheeks distende'd by forcing the air at 
sufficient pressure from the lungs. The cheeks 
naturally resist the pressure, and force the air through 
the blowpipe. The operation requires some practice 
and a clear nose passage. There is practically no 
limit to the time a continuous blast can be kept up. 

The blowpipe flame is produced by holding the 
blast end of the blowpipe just above the wick of the 
taper and touching the flame ; the blast then causes a 
long blue flame to project. This flame is hottest at 
the tip, which is slightly brown. 

Typical Blowpipe Jobs.— Some of the photographic 
reproductions in this chapter show the methods of 
soldering comparatively light and heavy articles. Fig. 



BLOWPIPE SOLDERING 



47 



35 shows a lading-can handle being resoldered. As it 
had broken away, the old solder remained, and the 
joint did not need cleaning. It is dabbed with the 




Fig. 37. — Soldering Wires of Vegetable Masher 



Mrthi...: '"'"i 1 



■■■'!■■ ] 



Fig. 38. — Holder for Applying and Adjusting Solder 

killed-spirit brush, and a small piece of solder put near 
the joint. The flame is first played on the parts away 
from the solder to get them to the requisite heat, and 
as the heat reaches the solder it melts, and flows where 



48 SOLDERING, BRAZING AND WELDING 

required. Where the solder should be the thickest, 
that part of the joint is inclined downwards. 

A job needing very much heat, and therefore a con- 
tinuous blast for some time, is shown by Fig. 36. A 
lug is shown being soldered to a heavy brass lamp 
bottom. Before putting the lug in position the parts 
of the joints have to be tinned. This consists of apply- 
ing a film of solder. In this case the heat is applied 
to the lamp bottom for several minutes, and without 
loss of time the part where the lug fits is cleaned with 
a fine file, the spirit brush dabbed on a piece of solder, 
put in position, and the flame again applied. The 
solder almost immediately flows over the cleaned 
portion; if it does not flow as required, the flame is 
played on the solder and lamp bottom, a dab with the 
spirit brush helping matters. The lug, which should 
have been previously tinned, is placed in position on 
the lamp bottom, and with a slight application of the 
flame, the solder flows and unites the parts firmly 
together. It should be particularly noted that, when 
uniting light articles to heavy ones, the light ones 
should be tinned first, and secured to the heavier 
article whilst the latter is still hot. 

Fig. 37 shows the wires of a vegetable masher being 
soldered. There is nothing special about the job, 
except that the solder cannot be placed on the joint. 
To effect this a piece of tin (Fig. 38) is indented at 
one end, and a small hole made in the centre of the 
depression. The bead of solder is placed in this 
depression, and held over the joint to be soldered; the 



50 SOLDERING, BRAZING AND WELDING 

flame is then played on the joint and on the solder 
which flows through the hole. 

Figs. 39 and 40 show the method of tinning a 
brass dial ring. The ring is filed clean and placed on 
a piece of asbestos board, the flame being applied until 
the ring is sufficiently hot all round. A bead or two of 
solder is placed on, and, as they melt, the solder is 
brushed round as shown in Fig 39 with the spirit 
brush, the flame being applied at intervals to aid the 
flow. 

Re-soldering Kettle Spout.— Eefixing a spout in a 
"tinned " wrought-iron or copper kettle. The spout and 
that part of the kettle which comes in contact with it 
should first of all be filed bright and clean. Next place 
the spout in position, apply killed spirits, and hold it 
over a bunsen flame, as in Fig. 41, until sufficient 
of the strip solder is melted to flow around and sweat 
through to make a strong sound joint. Should any 
difficulty be experienced in getting the solder to flow 
readily, apply a little more flux. 

Soldering Corroded Metal. — When the surface of 
metal to be soldered is badly corroded, and it is 
difficult to obtain a clean, bright surface preparatory to 
soldering, it should be treated to a liberal application 
of raw spirits of salts (hydrochloric acid), which will 
soon remove the cause of the trouble, but all traces of 
the acid should be washed away with clean water before 
attempting the soldering. It is also a good plan in 
these cases to tin the surface by repeatedly rubbing it 
with a hot bit and solder, together with plenty of killed 



BLOWPIPE SOLDERING 



5i 



spirits, before proceeding with the actual soldering 
process. 

Soldering Small Work. — When soldering two 
small awkward-shaped pieces together, they can be 
held in position by pressing slightly into a piece of 




Fig. 41.— Re-soldering Kettle Spout 

damp clay. When the work has several soldered 
joints it can be buried in sand or covered with clay to 
confine the heat to the part being operated on. 

Although care should be taken to limit the solder 
to the area of the joint, there are circumstances in 
many cases where it is difficult to prevent some of it 
from straying. To clean this off, resort may be had 



52 SOLDERING, BRAZING AND WELDING 

to the blowpipe, applying the blast and quickly wiping 
the surface while the solder is in a molten state. Or 
it may be filed off while cold and finished with a 
scraper or a knife and emery-cloth. Or if there is only 
a thin film the knife or emery-cloth alone will suffice. 

Soldering Pipe Joints.— Most joints in lead, tin 
and compo. pipe are now preferably made by means of 
a blowlamp, or with a mouth blowpipe, strip-solder 
being used. When making the joint, heat the pipe in 
the immediate vicinity, and, dipping the solder in the 
flux, stroke it around the pipe to form the joint. 

In soldering block tin or compo. pipe with a bit, if 
this is too hot ft will promptly melt the pipe. This is 
also liable to happen with very thin zinc. The only 
way to prevent this is to have the bit just hot enough 
to melt the solder, and not to let it rest any length of 
time on the soft metal. 

In making connections with soft pipe it is better 
to make use of brass couplings, and these can be 
soldered more easily and safely by means of the blow- 
pipe than with a bit. First clean and tin both ends 
of the coupling, and with the bit put a little ring of 
solder round about J in. from the end, as shown at d 
in Fig. 42. Next with a penknife cut a hole in the 
pipe b where the connection is wanted, a neat fit for 
the end of the coupling tail A, scraping the surface of 
the pipe all round the hole. Insert the coupling in 
the hole in a vertical position. Sprinkle a little 
powdered resin round the joint, or smear it with fluxite. 
Using the flame of a spirit lamp or a candle and a 



BLOWPIPE SOLDERING 



53 



mouth blowpipe, heat the upper part of the coupling, 
being careful not to allow the flame to come too near 
the soft pipe. The solder will soon melt, and run 
down into the joint (see d in Fig. 43), w T hen the flame 
must be instantly withdrawn. The same proceeding 
can be adopted in soldering the other portion of the 
coupling into the connecting pipe. If a vertical 
position is inconvenient for the coupling it can still be 



Fig. 42 




Fig. 43 



Z~L 







Kgs. 42 and 43. — Soldered Branch Joint on Tin or Gompo. Pipe 

soldered in that position, and afterwards twisted care- 
fully into the desired position. In Figs. 42 and 43, c 
represents a wood plug for steadying the coupling tail. 
Soldering Birdcage Wires. — For this job, it is 
better to flatten out the solder to the thinness of brown 
paper and with a pair of scissors or shears to cut it 
into very narrow strips. Take little pieces about \ in. 
long, and with the fingers pinch them round the wires 
just above the joints to be soldered. Touch each joint 
with a small quantity of killed spirit, and apply the 
flame of a small blowlamp just underneath the joint; 



54 SOLDERING, BRAZING AND WELDING 

this will cause the solder to run in the joint in an 
instant (see Fig. 44). The flame is quite free from 
smoke, and does not discolour the wire in the least, as 
the solder will run long before the wire is red hot. 
Every joint may thus be neatly made. With a thin 
piece of copper wire secured in a handle as illustrated, 
the solder may be drawn any way desired to make 
special joints in awkward places, where the point of an 
ordinary soldering bit could not be used. 

Sweating.— In the preceding chapter it was shown 
how useful sweating is, when accomplished with the 
help of the bit. In blowpipe work, also, this method 
is of much utility, particularly in delicate work where 
portions have to be joined up in very precise relations. 
Mper tinning the joint faces the pieces are secured in 
accurate relationship with binding wire, or by bolts or 
screws or other means, or a soldering clamp is 
employed, having jaws which clamp the pieces and 
enable them to be adjusted to the exact locations 
desired, and the flame then brought to bear until the 
work is hot enough to cause the solder to run. 

An example of the usefulness of sweating occurs in 
the making or repairing of metal name plates having 
superimposed brass, copper, or other metallic letters. 
The plate having been flattened and polished and the 
letters cut out, filed and finished, the backs of the 
letters must be rendered chemically clean by careful 
scraping, and are next "tinned" with soft solder. 
The tinning may be done in several ways, but the 
easiest is by the blowpipe, using resin oil as flux. 



BLOWPIPE SOLDERING 



55 



Each letter may be placed in succession on a lump of 
charcoal, using plenty of the resin oil, and applying 
the flame of the blowpipe to the surface while one 
hand holds the charcoal and the other the strip of 
solder. To prepare the solder, w T hich is sold in sheets 
by the pound, cut some strips J in. wide. Take hold 
of one end 1 in. from the end, and with a sharp knife 
scrape the surface, drawing the knife edge downwards. 




Fig. 44. — Soldering 
Birdcage Wires 



Do not use the last 2 in. of the strip, as the handling 
of this part makes it chemically unclean. The greater 
part of the solder should be about the edges of the 
letters. The next operation is to solder the letters to 
the brass plate. As the brass plate also must be 
chemically clean, the parts where the letters are to go 
should be lightly scraped. Having ruled parallel lines 
in order to get the letters in line, lay each down in 
its proper place, and draw a pencil line round it ; then 
with a scraper just remove the surface of the brass 
where the letters are to be soldered. A thin piece of 



SS SOLDERING, BRAZING AND WELDING 

solder is now placed underneath each letter, and each 
in turn is fixed in its place and secured with a loop 
of binding wire screwed up tight. Nothing now 
remains to be done but to apply the blowpipe flame 
and resin oil, when the solder will run underneath the 
letters. It is better to set the plate on some small 
lumps of charcoal. When the letters appear to be 
set fast, remove the plate and boil it in a solution of 
potash, about J lb. to 1J gal. of water, and clean in 
dry sawdust. The resin oil may be made by dissolving 
resin in sweet oil by gentle heat, until the oil will 
cause the solder to run. 



CHAPTEK VI 
Soldering Aluminium 

It is well known to those accustomed to the art of 
soldering that there is no solder which operates with 
aluminium in the same way that ordinary solders 
operate with tinplgite, copper, brass, etc. Aluminium 
soldering presents so many difficulties that it has been 
thought desirable to devote a separate chapter to the 
subject. 

There is more than one reason for the difficulty 
encountered. Aluminium does not alloy readily with 
solders at temperatures as low as other metals require ; 
and, secondly, aluminium alloys with lead solders only 
with great difficulty, and with but a small proportion 
of lead at that. Consequently, lead solders are not 
suitable for aluminium. Another and even more 
serious reason is in respect to the refractory oxide which 
forms at soldering temperatures, and which is un- 
doubtedly responsible for most of the trouble. 

The soldering of aluminium is one of the most 
debated subjects in metal working. Almost as soon 
as aluminium was prepared on a large scale, it was 
discovered that the ordinary solders and fluxes did not 
answer with it. Either pure tin or pure zinc will wet 
aluminium, and can, therefore, be used as solder for 
it ; experience shows that the tin soon falls apart, while 

57 



58 SOLDERING, BRAZING AND WELDING 

zinc by itself is brittle and discolours badly. The 
failure of tin is due to the fact that it forms with the 
aluminium an alloy that is decomposed by the action 
of the oxygen present in the air. 

Although aluminium is popularly supposed to be 
non-oxidisable , really the surface is covered with a 
very thin film of oxide, which prevents solder from 
alloying with the metal. Aluminium when heated 
rapidly oxidises. It is customary to scrape the metal 
before and during the soldering ; and although some 
workers say that it is useless to scrape before soldering 
because oxidation immediately starts again, it is 
obvious that a thin film is more easily penetrated than 
a thick one. Often it answers to scrape with the 
copper bit during the soldering, previously rubbing off 
the oxide with emery cloth. The work should, if 
possible, be backed with asbestos, to keep up heat in 
the metal. To discover whether the surface is 
thoroughly tinned, wipe off lightly, and the untinned 
parts will then soon become apparent. If the oxide 
is not scraped off beforehand, it will probably mix 
with the solder and form a scum, which will make a 
neat flow difficult. Scum should be lightly removed 
with an old knife blade. It is essential to "tin " every 
part to be joined, as the solder will not take on any 
spot that has not been rubbed in some way, unless 
previously coated. 

Solders for Aluminium.— Hundreds of aluminium 
solders have been invented, naturally all claimed to 
be strong and durable, the alloys containing various 



SOLDERING ALUMINIUM 



59 



metals, such as aluminium, antimony, bismuth, 
cadmium, chromium, copper, lead, manganese, silver, 
phosphor tin, tin, and zinc. A table of the most 
approved aluminium solders is here given. 

Many of the best solders for aluminium contain a 
small proportion of phosphor tin. A molten alloy con- 
taining phosphorus placed on aluminium tends to 
absorb oxygen from the impure film as well as the 
surrounding air. 

In making the solders here given, it is advisable 



Compositions of Aluminium Solders 



Tin 


Zinc 


Silver 


Alumi- 
nium 


Cop- 
per 


Bis- 
muth 


Phos- 
phor 
Tin 


Cad- 
mium 


Lead 


Anti- 
mony 


72-5 

80 
97 
20 
90 
65 
30 
99 
90 
6 

80 
75 
70 


25 
20 

27 

20 

77-5 

90 
80 
80 
90 
17 
22 
25 


10 
5-75 


1-5 

70 
10 
2-25 

3-25 

6 
12 
20 

5 

2-25 

2-5 

3 


1 
9 

4 

8 


3 
1 


1 

•75 
•5 
2 


50 


3-25 


5 



to avoid loss of the more easily volatile of the metals 
by adopting the following precautions : The aluminium 
is melted first, the zinc is added in small pieces, then 
tin in small pieces, and lastly the phosphor tin. 



6o SOLDERING, BRAZING AND WELDING 



Inasmuch as zinc alloys with aluminium more 
readily than does any of the common metals, solders 
that will readily "tin" aluminium generally contain 
zinc in varying proportions. The solders found most 
satisfactory contain zinc, tin, aluminium, and a very 
small proportion of phosphor tin ; but they do not run 
very freely or fuse so readily as the ordinary tin and lead 
solders, and it is necessary to use a higher temperature, 
so high, in fact, that difficulty is found in using these 
solders with a soldering bit, and it is generally neces- 
sary to use a blowlamp. 

While there is no solder that allows aluminium to 
be soldered with the facility and success experienced 
with other metals, that of Ri chard's is extensively used, 
and seems to have given as good results as any. It 
consists of the following ingredients : Tin 29 parts 
zinc 11 parts, aluminium 1 part, and 5 per cent, 
phosphor tin 1 part — practically the same as that given 
in the last line of the table. This solder has with- 
stood the test of time better than many of the patented 
solders, and can be used in jointing aluminium to 
aluminium, also aluminium to copper or brass, and 
without the use of a flux. In making the solder it is 
advisable to avoid loss of the more easily volatile of the 
metals. The aluminium should be melted first, then 
the zinc, tin, and phosphor tin in the order named. 

When using phosphorus instead of phosphor tin in 
the making of aluminium solder, it will first be neces- 
sary to incorporate it with the tin, for which purpose 
take a length of 1-in. gas barrel, attach a screwed 



SOLDERING ALUMINIUM 61 

cap at one end, and close the opposite end with a tin 
(not tin-plate) ping. Remove the screwed cap, and, 
having carefully dried between blotting paper the 
proper proportion of phosphorus, insert the latter in 
the tube and replace the cap. Now put the plugged 
end of the tube into the molten tin ; this will melt the 
plug of tin and so allow the phosphorus to come in 
contact with the molten metal. The ingot of 
phosphor tin formed is afterwards alloyed with the 
other ingredients, as already explained. 

Fluxes for Aluminium. — A large variety of fluxes 
have been tried with more or less success, namely, 
borax, copper chloride, lithium chloride, paraffin 
resin, sal-ammoniac, stearin, silver chloride, tin 
chloride, Venetian turpentine, tallow, vaseline, and 
zinc chloride. Stearin is undoubtedly the most 
reliable of them all, but no flux is needed for solders 
containing phosphorus, which is itself a flux. 

The Soldering Bit. — The average temperature re- 
quired to make a satisfactory and thoroughly sweated 
joint in aluminiuifi is from 650° F. to 680° F., accord- 
ing to the size of the article. A blowpipe or blow- 
lamp will be of great value, and is frequently pre- 
ferable to a bit. Should a bit be used, see that it is of 
aluminium or nickel instead of copper, the point and 
the soldered joint being kept much cleaner whilst 
removing the film of oxide during the soldering opera- 
tion. Another advantage is that the point or "face " 
of the bit can be "tinned " with the same flux as that 
which is used for the joint. More care must be taken 



62 SOLDERING, BRAZING AND WELDING 

in the manipulation of the aluminium soldering bit 
owing to its lower melting temperature than the copper 
and nickel bits. 

The Process of Soldering Aluminium.— The solder- 
ing of aluminium must be performed quickly to be 
satisfactory, as the metal, if not coated at the first 
attempt, may be injuriously affected. " Tinning " the 
parts required to be soldered first is another important 
factor ; also the distance of the overlap of the joints 
should not exceed more than J in., so as to allow the 
solder to flow thoroughly through ; it does &ot flow so 
readily as when soldering other metals. 

In soldering large pieces , where the ordinary over- ' 
lap is not allowable, and where a butt joint would be 
weak, fit the pieces together as at A (Fig. 45). 

Solder always flows towards the hottest point. 
This tendency enables one to direct its course under 
the blowpipe or blowlamp flame. A large flame should 
only be employed in "heating " up the part to be 
soldered on large and heavy work. With a small 
pointed flame directly on the solder and the parts on 
which it rests, the solder will flow quickly, and leave 
a smooth, even surface at completion. 

Some aluminium solders now on the market are so 
hard that it is necessary to heat them and the work 
to redness before they melt. Sheet aluminium is 
easily warped by heat, and also contracts badly. If the 
solder is too high in melting point, the metal must also 
be brought to that point to cause proper union. If a 
hole is being filled in, the body of the metal on heat- 



SOLDERING ALUMINIUM 63 



ing expands all round and partly closes the hole ; also 
both the solder and the patch whilst hot are slightly 
expanded. In cooling, the hole enlarges, the patch 
contracts, and the solder also contracts; cracks result. 
The body of the work, if not exactly evenly made, will 
warp, which is fatal to engine and similar work. By 
using a low-heat solder (melting point, about 700° F.) 
these troubles should be avoided. 

Soldering Aluminium to Copper or Brass.— 
Aluminium can be readily soldered to copper or brass 
with line solder (2 parts of tin and 1 part of lead) : tin 



£ 



Fig. 45. — Aluminium Fitted Together for Soldering 

the metals, using stearin as flux previous to making 
the required joint. It is essential that both the 
"tinning " and soldering should be thoroughly done. 
Do not expect the solder to pull the joint together, but 
see that the joint is kept under slight pressure until the 
solder is hard, otherwise the joint will not be perfect. 
Many workmen refuse to place any reliance in such 
joints. 

Finally, it seems very likely that, at any rate as 
regards factory work, the use of solder on aluminium 
objects will be wholly discarded in the future in favour 
of fusion welding or autogenous soldering, in which 
process no alloy is interposed between the surfaces to 
be joined. Information on the subject is given towards 
the end of this book. 



CHAPTEE VII 
Wiping Joints on Lead Pipes 

Plumbees make joints in lead pipes with soft solder 
which, by means of cloths, they "wipe " to the shape 
shown by Fig. 47. 

Figs. 46 and 47 show the difference between a 
copper-bit or blowpipe joint and a wiped joint. 

Plumbers' Solder. — As already stated, coarse, or 
plumbers' wiping solder, is made in the proportion of 
2 of lead to 1 of block tin. Care must be taken that 
the lead is quite pure and free from any other metal, 
as zinc-adulterated solder will be difficult to use, and 
joints made with it on service pipes will not be sound. 
In melting up scrap lead for making solder, only sheet 
lead should be used, as the lead used in the manufacture 
of sheets is much purer and contains a greater propor- 
tion of pure pig lead. The scraps must be quite dry ; 
a damp piece dropped into a pot of molten metal 
, may cause a serious accident , as the contents of the pot 
may be blown out. 

To test the quality of solder when made, heat it as 
for wiping a joint ; the correct temperature is deter- 
mined by dropping a small piece of newspaper into the 
pot, and if it quickly burns and catches alight the 
solder is right for using. Next pour a small quantity 

on to a cold but dry stone or cement floor, This, on 

64 



WIPING JOINTS ON LEAD PIPES 65 

cooling, should have a few spots on the surface about 
the size of a threepenny-piece, and on the under side 
should be bright nearly all over. Solder of this 
quality would, if properly used, stand any pressure 
without sweating. If the solder on the stone or 
cement floor looks white on both sides, or has a few 
small bright spots on the under side only, it is too 
coarse and requires more tin. On no account should 




Fig. 6 
Fig. 46. — Copper-bit Joint on 
Lead Pipe 

Fig. 47. — Wiped Joint on 
Lead Pipe 




Hg. 47 



the solder be heated to redness, as the tin rises to the 
top and quickly turns to dross (see p. 11). If this 
should happen to solder that is being used for service 
pipes, it should be rectified by adding more tin. 

To purify a pot of ''poisoned " solder (solder that 
contains zinc), melt, stir in a handful of common 
sulphur or powdered brimstone until the mass is of 
the constituency of wet sand, heat to the ordinary 
working temperature, and carefully remove the crust 



66 SOLDERING, BRAZING AND WELDING 

that forms on the top, and the solder will then be fit 
for use, except that a little tin must be added to it. 
The presence of zinc in solder can be detected by the 
difficulty of forming joints, the metal falling apart and 
working very lumpy, and the joints when finished 
having a dirty grey appearance. 

When plumbers' solder is bought ready for use from 
the manufacturers, it is usually in the form of casts of 
eight bars, weighing about 56 lb. to the cast. The best 
only should be used, as cheap solder is frequently the 
cause of much trouble if used on high-pressure work, 
and joints made with it are never of good appearance. 
To test manufacturers' solder, wipe a joint with it, 
and if it is of good quality it will work easily at a good 
heat, and when cleaned off with tallow and a clean rag 
it should be w r ell covered with bright spots. 

Brass fittings should not be tinned by dipping into 
the solder pot, as brass being an alloy of zinc and 
copper, the zinc may be melted into the pot with 
disastrous results. 

Flux.— The flux used is tallow, no other flux answer- 
ing the purpose so well, although mutton fat has been 
used as a substitute. Plumbers often call tallow 
"touch," and they frequently use it in the form of 
tallow candles, the cotton wicks coming in handy for 
packing spindles of taps and slides of gas pendants, 

An excellent plumbers' black, soil or smudge, can be 
bought in packets, and requires only to be mixed with 
water before using. Ordinary black consists of lamp- 
black, glue, and water. The black should be first 



WIPING JOINTS ON LEAD PIPES 67 

mixed with water, afterwards adding the glue, which 
must have been previously melted in a glue-pot. 
Simmer this for a time to remove surplus water. Test 
the black on a piece of sheet lead and dry off slowly. 
If it chips, add more black, but if it rubs off add glue. 

The black should be made in small quantities, as it 
deteriorates if kept. 

Another recipe is to place in the pot J lb. of size 
or diluted molten glue and a little water ; gently warm 
until the size dissolves, but do not boil. Mix J cub. 




Fig. 48. — Joints prepared for Jointing 



, 


_T~ 




! 












1 






% \ 





Fig. 49. — Marking-gauge for use on Pipe Ends 

in. of chalk ground to a fine powder with a penny- 
worth of lampblack, and then with a pallet knife in- 
corporate some of the melted size with the mixture on 
a flat board or stone to form a thin paste, after which 
place the whole in the pot, warm, and stir together 
thoroughly. Test as before. Old and thick soil is 
thinned with porter or stout, but do not add too much 
or the soil will become so sticky that the solder will 
cling to it. A little brown sugar, or a little stout, 
added to the black will make it more tenacious, and 
cause it to dry with a slightly glossy surface. Some 



68 SOLDERING, BRAZING AND WELDING 

plumbers soil their joints after they are made, with 
black japan or thinned Brunswick black. But it is 
doubtful whether the effect is so good as when a 
"dead " black, such as given by ordinary soil, is used. 
The Cloths. — Solder cloths for underhand joints 
should be from J in. to f in. w T ider than the joint for 
which they are to be used, and about J in. longer than 
they are wide. Most plumbers use the same cloths for 
underhand and upright, but it is preferable to use a 
special cloth for 4-in. upright joints with the length 
1 in. less than the width. For getting up the heat of 
an underhand joint on a small pipe a larger cloth may 
be used until the worker is sufficiently skilled in joint 
wiping not to burn his fingers when using the correct 
size. For 3-in. joints and upwards a large cloth must 
be used first to get up the heat, the wiping cloth 
being kept warmed and ready for use when the heat is 
right. This large cloth, as used by some plumbers, is 
often long enough to lay on the worker's arm, but 
this is clumsy to use when the joint to be wiped is in a 
cramped position, and is liable to let the pipe get burnt, 
as the metal it holds cannot be readily distributed round 
the joint ; 8 in. by 9 in. is a good size to practise with 
on the bench, and as more skill is obtained it can be 
reduced to 7 in. by 7 in. A diagonal strap should be 
stitched to the back to take the little finger and thumb ; 
the position for this can be obtained by laying the cloth 
face downwards and placing the hand on it with the 
finger slightly spread ; the wrist should be over the 
right-hand corner, so that when the cloth is being used 



WIPING JOINTS ON LEAD PIPES 69 

the edge is readily kept parallel with the sides of the 
pipe. Branch cloths are made from 1J in. to 2 J in. 
wide and about half as long again in width. These 
cloths should be about seven thicknesses of material, 
all others being nine or ten. 

White moleskin cloth is obtained from the tailor's 
for making these solder cloths, is usually 1 yd. 
wide, and costs about 3s. per square yard. The usual 
method of making cloths is to cut a strip down the 
selvedge of the material and fold up the strip till the 
desired size is obtained ; it can then be cut off the 
piece, and any odd ends left may be used for packing 
a larger cloth. Another method is to cut a square 
piece the required' size, and then fold it three times 
each way. This makes a rather clumsy cloth for small 
sizes, but makes a very good "blanket." 

Horizontal or Underhand Joints. — For making 
a successful wiped joint, the ends to be joined must be 
a good fit and the temporary fixing must be sufficiently 
strong so that the joints will not be broken in the 
process of wiping. These two points should be always 
strictly attended to. Service pipes should be tightly 
pressed home one in the other, the cupped or female 
end shaved inside with a knife, but not close in as is 
the case with soil or waste pipe ; this allows the solder 
to fill up the cavity, which effectually prevents any 
tendency to sweat. This principle is followed up by 
some plumbers with branch joints on small size service 
pipes, the male end being worked in with a twisting 
motion, to prevent any solder getting into the pipes. 



70 SOLDERING, BRAZING AND WELDING 

All other pipe joints should be closed, the female end 
being tightly worked in round the male end of pipes as 
an extra precaution against the solder getting inside. 
It is a good plan to black the inside of waste and soil 
pipes, so that the solder will not adhere if any should 
get through when making the joint. Fig. 50 shows 
the wiping of an underhand joint. 

Beginners often spend a lot of time practising 
" rolling " underhand joints. This is bad practice, and 
will be of no use in wiping fixed joints. Little advice 
can be offered with regard to the actual wiping, con- 
stant practice being the essential thing. See that the 
solder is at the correct heat. This is readily found by 
dropping a piece of newspaper into the pot, and, if it 
quickly browns, the solder is ready for use. If the 
solder is used too hot it will quickly burn holes in the 
pipe, and if not hot enough a heat cannot be properly 
worked up, and the cloth may get torn trying to move 
hard metal. For underhand joints pour on steadily 
with a circular motion on to the sides of the joint, and 
on to the soil at the ends of the joint, until sufficient 
solder in a molten condition can be brought up to cover 
the top of the joint with the cloth, which is held 
underneath it ; then pour steadily all over the solder 
until it runs back again. Eepeat this continuously 
until the solder can be worked in a substantial body all 
round the joint without any hard solder being left at the 
underneath edges. Give the joint a last pour on, and 
wash all the solder into the cloth. Bring the solder 
smartly on to the top, and quickly work it all round the 



WIPING JOINTS ON LEAD PIPES 71 

joint with the wiping cloth, using two fingers of one 
hand for the top and back edges, and the index fingers 
of both hands for the underneath part. The top of 
the joint should be roughly shaped first and the surplus 







e 



72 SOLDERING, BRAZING AND WELDING 

metal brought over the back to the underneath ; this 
should be worked into the bottom of the joint with a 
slight sideways motion. The extra body of metal 
should be used to warm up any hard edges, the surplus 
being brought up again to the top and quickly thrown 
off to the back. 

Upright Joints,— These are more trying to the 
worker's patience but are the easier to wipe. After 
the pipe has been fixed in position, a lead collar should 
be fixed a few inches below the joint to catch the 
surplus metal. A piece of stout string tied by a half 
hitch round the pipe will prevent any leakage of the 
solder. In working up the heat of an upright joint, 
care should be taken to work steadily round the joint 
so that the heat is the same throughout. After suffi- 
cient metal has been splashed on with the splash stick 
and ladle, and the metal is at a moving heat, roughly 
shape up the joint with the splash stick, keeping the 
metal fairly high on the joint; then splash on a little 
more hot metal all round. A warm cloth is now used 
to shape up the joint by bringing the lower metal up to 
the higher part, after which start to wipe first with the 
hand as far round the back of the joint as possible and 
bring the surplus metal to the front, the cloth being 
held by the thumb and the index and little fingers ; then 
change the cloth to the left hand and repeat the opera- 
tion. The joint should be finished off at the back, 
although if quickly done the finish off should not be 
apparent. The collar must now be taken off and the 
solder it contains melted with a plumber's iron. 



WIPING JOINTS ON LEAD PIPES 73 

A plumber's iron can be used to good purpose on 
these joints, especially if they are out of doors and the 
weather is rough. The iron must be heated to red- 
ness and well filed up. 



r~"~i 


JUT T — ~^~~ — ' ) 


t if 




/ i 




t il 


J 


V L 








/ r-ztt 1 


\ ■ fegjiil^ / 


J NpSp=^^ | \ 


u Jf 




t d 


~\ 


/ 1 


J 


\ 


~( 


a j i 


1 


V 1 


J 


L.i. j SL 


IIIm — . — i — L_ — J 



Fig 52. — Making Upright Wiped Joint 




Fig. 53. — Wooden 

Collar or Platform 

to Catch Waste 

Solder 




Fig. 54. — Lead 

Collar to Catch 

Waste Solder 



ran k 



Fig. 55. — Pipes fully prepared for Jointing 



Where possible, all joints to be wiped in their per- 
manent position are sprung away from the wall and 
temporarily fixed with steel points made from J-in. 
hexagon steel about in. long and drawn out to a point 



74 SOLDERING, BRAZING AND WELDING 

at one end. In some cases, more particularly soil-pipe 
work, the pipes cannot be fixed away from the wall; 
a hole must then be cut into the wall about 4 in. back 
and about 12 in. square to allow the joint to be pro- 
perly made at the back. 

Wiped Joint between Lead and Cast-iron Pipes.— 
In wiping a lead pipe to a cast-iron pipe perhaps the 
best practice is to file clean the end of the cast-iron 
pipe first and then coat with pure tin, sal-ammoniac 
being used as a flux. The pipe then is washed to 
remove the sal-ammoniac, and afterwards "retinned," 
using resin and grease as a flux. A plumber's joint 
then is wiped in the usual way. It is necessary to 
take great pains to make a good sound strong joint 
between the two metals, but even then in the course of 
time (it may be only a few years) the iron w T ill come 
out of the solder. The first sign of decay will be a red 
ring of iron rust showing at the end of the joint. This 
rust will swell a little and cause the end of the solder- 
ing to slightly curl outwards. Eventually the rust will 
creep between the solder and the iron and destroy the 
adhesion of the one to the other. The joint would 
eventually become a loose ring on the iron pipe, but 
not on the lead pipe, as the expansion of lead and 
solder do not differ to any great extent. Only those 
metals that alloy together can be satisfactorily joined 
by soft soldering, and the solder should contain as great 
a proportion as possible of the metals to be united. 

The illustrations to this chapter (Figs. 46 to 55) are 
self -explanatory . 



CHAPTEE VIII 

Hard-soldering with Silver Solder 

Hard -soldering is chiefly of two kinds, brazing and 
silver-soldering, the former being employed for iron 
and steel, the solder used being known as " spelter," 
a brass alloy which can be obtained in various degrees 
of fineness. For copper, brass, and nickel silver, 
alloys containing silver are the best solders. In both 
forms of hard-soldering, the flux is borax. 

The methods of silver-soldering vary with the size 
of the work. A jeweller may hold the work in his 
hand, on the end of a piece of binding wire or on a 
square of charcoal, the heat being applied by a mouth 
blowlamp from a horizontal gas jet, as already 
described. Larger work demands a flame of greater 
intensity, and sufficient air can be supplied only by a 
footblower or similar device, or, as an alternative, from 
the flame of a suitable blowlamp. 

Silver Solder. — This can be purchased at prices up 
to 3s. 6d. or so per ounce in sheet form, about ^ in. 
thick. Where the solder is melted down by the 
amateur, a good way to obtain the sheet form is to 
turn the globule of molten metal on to the bench and 
to place a flat iron on it ; but the result will not be 
equal to a rolled ingot. 

An old shop method of making silver-solder is to 

75 



76 SOLDERING, BRAZING AND WELDING 

melt up old silver (using current silver coinage is an 
expensive method of obtaining the silver, and is said 
to be illegal) with some brass pins, not the iron ones so 
common now. 

According to W. H. Jubb, two solders compulsory 
for silver articles that have to be sent to assay for hall- 
marking are : (1) 12 parts standard silver and 1 part 
brass; (2) 6 parts standard silver and 1 part brass. 
No. 1 has a low melting point, and is termed "quick/' 
and No. 2, which requires a higher temperature, is 
called "stark " (in some parts of the country, "fine "), 
but the use of this term here is misleading. No. 2 
should be used at the first heating and No. 1 at the 
second. These should make ideal solders for 
beginner's use, as the chances of burning the work, 
even thin brass, are almost nil. 

(3) 2 parts brass, 1 part standard silver ; (4) 5 parts 
brass, 2 parts standard silver. Whereas Nos. 1 and 2 
are "silver solders/' Nos. 3 and 4 are termed "German 
silver solders," as they are not so white and are used 
on German or nickel silver (an alloy of copper and 
nickel). Both Nos. 3 and 4 are good, have a com- 
paratively low melting point, are much less expensive 
than Nos. 1 and 2, and, if plenty of wet borax is used, 
will "strike up " well. No. 3 is recommended. 

" Standard silver " is about 95 per cent, pure silver. 
Old "sterling silver ".is 925 per cent, pure silver. 

In making any of the above solders the brass and 
silver should be melted together, and care should be 
taken to see that the metal is clean beforehand. 



SILVER-SOLDERING 



77 



Where large quantities of solder are made, the metals 
are scoured with emery cloth before they are put into 
the crucible. 

Requisites for Silver-soldering.— For light jobs in 
silver-soldering the special tools and materials required 
are as follow: Suitable gas jet or other flame, mouth 
blowpipe, scraper, jar containing a sulphuric acid 
"pickle," piece of slate, camel-hair brush, pieces of 



ftncf 



5 /t6 



( So» 



Saw cut 



* 




Fig. 56 




Figs. 56 and 57. — Clip for 
Holding and Applying 
Silver Solder 



V- 



8*$z" f r "P or & * r °""d »%/tre 




Fig. 58. — Pricker and Spatula for Consolidating Joints and 
Applying Solder 



lump borax, two grades of silver solder, charcoal block, 
iron binding wire. 

The pickle is made by pouring 1 part of common 
sulphuric acid into 20 parts of water, and its function 
is to remove all dirt and borax from the metal. 
Silver-soldered articles should not be thrown into the 
pickle until they are nearly cold, as otherwise the joints 
may crack, but in the preparatory annealing (that is, 



78 SOLDERING, BRAZING AND WELDING 

softening) of plain metal, wire, rod or tubing, the 
article may be put into the pickle when hot — but take 
care of the splashes ! Plunging hot copper or brass 
into cold water does not have the effect of hardening 
it. Before placing a job in the pickle, remove any 
iron binding, as this is immediately attacked by 
the acid. 

Often it is advisable to heat the metal and put it 
44 through the pickle " before working on it, especially 
in the case of tubing that has been lying by for some 
time and has become dirty. 

For heavier work, a foot-bellows and gas blowpipe, 
or else a blowlamp, are essential. An "ZEtna " paraffin 
blowlamp with horizontal burner will be found quite 
satisfactory, although, of course, if a gas supply is 
available in the workshop the user will find that a foot- 
bellows and blowpipe are more convenient. A blow- 
lamp or blowpipe requires a suitable tray or " forge " 
of sheet-iron in which coke and odd pieces of brick or 
tile may be laid and used to pack round the object 
whilst the flame is being played on the part to be 
soldered. 

Among the smaller additional tools that will be 
required will be a clip to hold the solder (Figs. 56 and 
57) and a brass pricker (Fig. 58). 

Preparing the Borax Flux. — Make up the flux on 
the slate by rubbing on it a piece of the lump borax 
moistened with water. This paste may be applied 
with the camel-hair brush to the parts to be jointed. 
The flux prevents the oxidisation of the surfaces, which 



SILVER-SOLDERING 79 

would resist the amalgamation of the metals and the 
solder. 

The Method of Silver-soldering.— In hard-solder- 
ing with silver solder, first file or scrape the parts 
bright, and cover them and the solder with the borax 
paste. Heat gently at first so as to harden the borax ; 
then continue to heat by blowpipe until a red heat is 
reached, at which the solder will run. The secret is 
to blow continuously until the solder runs, and not to 
stop half-way. 

For soldering a silver watch case, an ordinary easy- 
running silver solder, which melts at a lower heat than 
silver, will do. But to make sure, shred the solder 
into very thin strips, and apply plenty of borax to them 
as well as to the joint to be united. Use the blowpipe 
gently at first so as to bake the borax, then heat the 
case all over almost to the melting point of the solder, 
and direct the flame to the part to be soldered until 
the solder runs and glistens. Cease blowing instantly, 
and plunge the case into a solution of sulphuric acid 1 
part and water 10 parts, to whiten it; then wash in 
hot water and dry in sawdust. Be careful to remove all 
steel springs before soldering the case. 

Soldering Small Work with Paillons.— These are 
small squares, say, J in., of sheet silver solder, made 
by using the snips as in Fig. 61, and prepared by well 
covering with the borax paste. Each paillon is placed 
in position with the tip of the brush, this job requiring 
a little practice. The solder should be clean, and if not, 
should be made so by passing through the fire and 



80 SOLDERING, BRAZING AND WELDING 

pickling. The work with the paillons in position 
should be slowly heated by blowing the gas jet on a 
part of the job farthest away from the solder ; the 
borax will dry, and should the solder have -moved, 
replace it with a suitable tool or the point of the wet 
camel-hair brush. The heat must not be applied too 
suddenly at first, otherwise the borax will boil up and 
push off the pieces of solder. The heat may be 
increased when the bubbling has ceased. Do not hold 
the work too far away, or it will get dirty in the smoke 
of the flame, or j^et too near, else the gas will not be 
used to advantage. As the work begins to get hot, 
slowly work the flame towards the joint until the solder 
melts and runs into the joint. Give it now a little 
extra heat to get the solder thoroughly down into the 
crevices, and then let the work cool down. When 
nearly cold twist off the iron binding wire and put the 
job into the pickle. Leave the work in the pickle about 
ten minutes, when all the borax will be dissolved. 

Larger Work. — An example of silver-soldering 
larger work is the joining together of two pipes, one 
smaller than the other. The best course to adopt is to 
file or scrape the end of the smaller and the inside of 
the larger (reaming and filing them if necessary) until 
a good fitting joint is obtained, as in Figs. 59 and 60. 
A strip of solder is then cut off, and, after the joint is 
well coated with borax paste, this solder may be- 
wound rpund the smaller pipe. If the joint is soldered 
in a vertical position, the larger pipe should be the 
lower. The heat should be conserved by laying the 



SILVER-SOLDERING 



81 



work in the coke and building the same round, or, if 
the work is too large or the joint in an awkward part 
of the pipe, a shield of tin plate or iron should be 
placed behind the joint so that the flame is thrown 
back on to the work. Should the pipe be attached in 
close proximity to the joint to a heavy piece of metal, 
then w r arm this metal up first, otherwise all the heat 
will travel to this part, and the work will take much 
longer to get to the proper temperature. In all cases 
where one part of the joint is of heavier substance than 



i-l 



s 



Joint 



Fig. 61 —Cutting Up 

Silver Solder into 

Paiilom 



*/>* — 




Fig. 59.— Section through 
Pipes prepared for Silver- 
soldering 



- Coil of 
Soider 



Fig. 60.— Pipes 
prepared for 
Silver-soldering 



the other, that part should receive the greater amount 
of attention from the flame. 

Quenching Silver-soldered Work.— Many crafts- 
men object to the cooling of the work by plunging it 
into water or pickle whilst it is hot ; but no damage or 
cracking of the joint occurs, it is thought, if the work 
is not plunged when it is red hot or anywhere near red 
hot. Plunging into a pickle certainly cracks the burnt- 
in borax, which can be readily removed and the joint 
examined to better advantage. Many a silver-soldered 
G 



82 SOLDERING, BRAZING AND WELDING 

joint has been passed as quite sound when it has only 
been the borax that has been stopping the interstices, 
and only after it has been placed under service for some 
time does the faulty joint make itself apparent. 

Silver-soldering cannot be done on work that has 
been previously soft-soldered unless the soft-soldered 
part is first cut away; but, of course, soft-soldering 
can be readily accomplished after silver-soldering or 
brazing so long as the work is clean and all burnt borax 
is first removed. 

Removing Soldering Marks. — Solder will run away 
from a part of a joint instead of running into it when 
the edges of the joint have been imperfectly cleaned 
preparatory to the application of flux and solder; also, 
if some dirt has got into the flux, or on the paillons of 
solder employed. Another cause is unequal heating 
of the joint, or allowing it to expand too much whilst 
being heated. The resulting fire marks may be 
removed by warming the articles on a pan over gas, 
and plunging them whilst warm into the sulphuric 
acid pickle. Or the marks may be removed in a hot 
and strong solution of potassium cyanide, and the 
polish renewed by a light polishing with a revolving 
swansdown mop and rouge composition. 



CHAPTEE IX 
Soldering Gold and Silver Jewellery 

Two methods of soldering are in common use among 
jewellers and silversmiths. Soft-soldering is done 
with fine solder (1 of lead and 2 of tin) i and is used for 
articles that will not bear much heating. The metal 
is filed or scraped clean and bright where the solder 
is wanted to run, killed spirit is applied, and a little 
solder is run on the surfaces by applying gentle heat. 
Having thus been "tinned," the parts are placed 
together and heat applied until they unite, a spirit lamp 
or a blowpipe being used. This is the sweating pro- 
cess, already referred to a number of times. 

For soldering catches and joints to cheap metal 
brooches that have been silver-plated or gilt, the same 
solder is used as in the above. Both catches and joints 
can be cheaply purchased, hard-soldered on to small 
plates, square, oval, or crescent shaped, to suit all kinds 
of brooches, Take one of these and hold it with an 
old pair of soldering tweezers in the flame of a spirit 
lamp, and give it a coating of solder on its under side. 
First wet it with the killed spirit, and then place a 
small portion of solder on it, and hold it in the flame 
until it flows all over the plate. It can be assisted to 
flow evenly by a copper wire, which is also useful to 
apply the acid flux. Having "tinned " the catch, clean 

83 



8 4 SOLDERING, BRAZING AND WELDING 

(by scraping bright) the brooch, and place the catch in 
position. Direct a gentle blowpipe flame to it until it 
is seen to settle down and the solder flows. Then 
wash it immediately in warm water to remove the acid 
and dry in sawdust, kept in a warm place. Use as 
little solder as possible, and only clean the brooch 
where the solder is required to run. Attention to these 
points will ensure a neat job. 

Hard-soldering on jewellery, etc., is done 7 with silver 
or gold solder, and requires the articles to be heated to 
a bright red. The parts are cleaned, and a paste of 
borax and water is applied as a flux. A small piece of 
the solder is also dipped in the borax paste and laid 
over the join. Gentle heat is first applied to bake the 
borax hard, then by the use of a blowpipe the parts 
are raised to a red heat until the solder runs. The 
instructions given in the preceding chapter apply 
generally. 

With regard to gold-cased jewellery, it is useless to 
attempt to hard-solder gold that has the least trace of 
soft solder or lead on it ; the heat causes the lead to 
heat into and rot the gold, and the articles will tumble 
to pieces. The only way to mend, say, a gold-cased 
lead ring is by soft-soldering a tin band or plate over 
it, applying the heat very gently to avoid melting the 
lead inside. 

For hard-soldering a gold ring without discolouring 
it, use solders containing gold, the precious metal in the 
solder being afterwards laid bare by a process of 
annealing and pickling. The solders are prepared to 



SOLDERING JEWELLERY 85 

suit the quality of the gold to be soldered, so that they 
may "colour " well and thus hide the joint. The fol- 
lowing is a list of coloured solders : 

Best solder: Fine gold, 12 J parts; fine silver, 4 J 
parts ; copper, 3 parts. 

Medium: Fine gold, 10 parts; fine silver, 6 parts; 
copper, 4 parts. 

Common : Fine gold, 8J parts ; fine silver, 6 J parts ; 
copper, 5 parts. 

The gold solder is cast in long ingots, rolled thin 
and flat, and cut up or filed into dust, and thus 
applied to the cleaned joints, using borax as a flux. 
After the joint has been closed under a blowpipe flame, 
the whole ring is annealed on an annealing plate to a 
dull red heat, then cooled, pickled in acid, and 
polished. The film of grease left by the polishing 
process is washed off in hot soda water, and the ring 
dried in hot sawdust. Hard-soldered rings may be 
coloured with a film of electro-deposited gold. 

If the gold is of common quality, under 12-carat, 
to remove any excess solder make a mixture by reducing 
to powder 1 oz. of green copperas and J oz. of saltpetre 
and boiling in 5 oz. of water. This will crystallise 
when cool. Eedissolve the crystals in eight times their 
bulk of muriatic acid. For use, add boiling water, and 
place the gold in the hot mixture. For gold of 12-carat 
or over, nitric acid and water (1 part of acid to 2 of 
water) will dissolve the solder without injuring the 
gold. 

Gold solders used on gold articles are made from 



86 SOLDERING, BRAZING AND WELDING 

gold of the quality of the article — say, 18- or 15-carats 
— to which is added y^th or more of silver and ^th 
or more of copper. The quality of the solder is always 
a trifle inferior to the metal on which it is used, so that 
the solder may melt at a lower heat than the article. 
The melting point of 18-carat gold is 1995° F., of 15- 
carat 1992°, and 9-carat 1979°, while easy silver solder 
melts at about 1802° F. This shows that although 9- 
or 15-carat gold could be used to solder 18-carat, it is 
not possible to use 18-carat to solder 15-carat. The 
same principle applies to silver and brass ; and the 
quality of the solder has to be known before any 
attempt should be made to carry out the actual solder- 
ing of an article. Another important point is that thin 
gold articles, like brooches, will not bear so hard a 
solder as the same quality of gold will do when made 
up solid, as in the case of a bangle ring. Solder for 
18-carat and 15-carat is made thus : Take 1 dwt. of the 
gold, and add 2 gr. fine silver and 1 gr. fine copper; 
melt well together, and roll out thin. For 12-carat, 
the addition of 3 gr. fine silver and 1 of fine copper to 
the dwt. is advisable ; while for 9-carat the most useful 
solder is made from 1 part fine gold, 1 part fine copper, 
and 2 parts fine silver. 

Great care must be exercised in hard-soldering gem 
jewellery, as the stones are likely to be injured. 
Diamonds are the only stones that it is safe to heat to 
redness in soldering. Fancy coloured stones, such as 
rubies, emeralds, sapphires, topazes, amethysts, 
garnets aquamarines, or pastes must not be made hot. 



SOLDERING JEWELLERY 87 

A ring with any of these stones may be hard-soldered 
at the back if the stones are covered up with a pad of 
wet tissue paper to keep them cool; but if the solder- 
ing has to be done anyw^here near the stones, they must 
all be taken out by un-setting. 

Articles set with pearls, turquoises, opals, or cat's- 
eyes (these things are not really "stones ") will bear 
no heat whatever, and must all be taken out before 
soldering. 

In cases where it is very desirable to leave the 
stones in place, in order to prevent their bursting 
when heat is applied to the jewellery, cut a juicy 
potato into halves and make a hollow in both portions, 
in which the part of the ring having jewels may fit 
exactly. Wrap the jewelled portion in soft paper, 
place it in the hollow, and bind up the closed potato 
with binding wire. Now solder with easy-flowing gold 
solder, the potato being held in the hand. Another 
method is to fill a small crucible with wet sand, bury 
the jewelled portion in the sand, and solder in the 
usual way. 

To restore the colour of gold or silver after solder- 
ing, dip the articles while hot into pickling acid (1 part 
of sulphuric acid to 10 parts of water) ; or put them in 
a little acid in a pan and boil them in it. Here, again, 
diamonds are the only stones that may be dipped hot, 
and there is a slight risk even with them. Pearls, etc , 
must not touch the acid, either hot or cold. 

After heating and pickling, all gold is of a pale 
colour, and the commoner the gold the paler. How- 



88 SOLDERING, BRAZING AND WELDING 

ever, 18-carat gold may be restored to its original 
colour in a few moments by buffing with rottenstone 
and oil on a leather buff or on a brush, and following 
with rouge in the same way ; or it may be burnished if 
the nature of the article permits this. Poorer qualities 
of gold may be restored to their bright colour by the 
same means, but this takes longer. Most 9-carat 
articles are gilt to improve their colour, and after 
soldering must be re-gilt to restore their original 
appearance. 



CHAPTER X 
Brazing 

Habd-soldeiung" by brazing with spelter is used to a 
very great extent in the metal industries, especially in 
the manufacture of cycles and motor-cars. Although 
several mechanical joints have been tried in cycle 
manufacture, the greatest number of joints are made 
by means of brazing solder. A joint made in this 
manner is almost as strong as a weld, and the steel tube 
itself will often break under a strain and the brazed 
joint remain intact. Copper and brass tubes, when 
we]] brazed, will stand a pressure of 10 lb. or more per 
square inch. 

Spelter. — Hard brazing solder (spelter) is some- 
what difficult to make. The metals have to be melted 
in a crucible and cast at a proper heat, and while in a 
certain condition have to be pounded or punned in a 
mortar. This disintegrates the materials and forms 
crystals of various sizes, some being as coarse as wheat 
grains, varying in fineness down to that known as 0, 
which is very fine dust indeed, and used only on very 
particular work, such as tubing j in. or yq in. in 
diameter. The quantity of from 1 cwt. of solder is 
very small, the corresponding quantity of coarse grains 
being much larger; so that unless a quantity is 
required, it is cheaper to bay than to make. It is 

89 



90 SOLDERING, BRAZING AND WELDING 

necessary to employ the purest materials, and in 
purchasing hard solder it is advisable to state the pur- 
poses for which it is to be used. 

As a general rule, a solder should melt at a heat just 
under the melting point of the metals to be united. 
Now, in ironwork, or with the steel used in cycle 
work, this is impossible, for the melting points of these 
two metals are too high to be effected by the bunsen 
blowpipe or brazing hearth ; but to join two metals in 
which the melting point approximates very closely to 
that of the solder requires great care in order that the 
metals n^y not be fused and the join spoiled. The 
reason why the melting point of solder should be about 
the same as that of the metals being joined is apparent 
when it is remembered that heat and cold, vibration 
and concussion, tension and compression, have very 
considerable effect on metals, and that if the expansion 
and contraction of these under working conditions is 
not nearly alike, disruption or opening of the joint will 
follow. 

Hard solders or spelters are mainly composed of 
copper and zinc — that is, they are brass alloy — the 
quality most extensively used consisting of equal parts 
of copper and zinc. As the quantity of copper in the 
solder is increased, so the fusing or melting point is 
raised. 

Ordinary copper melts at about 2,000° F. and zinc 
at about 840° F., and a solder composed of equal parts 
of each metal has therefore a high melting-point. 

A very hard solder consists of equal parts of silver 



BRAZING 91 



and copper. Generally, a spelter of different com- 
position is required for iron, copper, and brass work, 
that for the latter being required more readily fusible 
than that for the former. A suitable spelter for iron- 
work is one composed of 2 parts copper and 1 part 
zinc ; a spelter for copper consists of 3 parts copper and 
2 parts zinc; while equal parts of copper and zinc 
make a suitable spelter for ordinary brass work. If a 
very low melting point be required, a little silver should 
be added to the last-given spelter. 

The Flux. — Borax is the best-known flux for 
brazing. It is beneficial, however, to have the borax 
calcined (fused), as it settles down to its work im- 
mediately when applied to the hot metal, whereas 
uncalcined borax has a tendency to swell and fall off 
the work. 

Spelter is in the form of filings, a thin stick, or 
wire. Filings are apt to be blown from the work. 
Brazing is a very useful, and, if properly done, reliable, 
method of joining two pieces of iron. A brazed joint is 
considerably stronger than a soft-soldered one, and 
easily resists temperatures that would cause ordinary 
solder to run. 

The process is not at all difficult if there is suffi- 
cient heat, and, for those who have no gas laid on, the 
purchase of a paraffin ZEtna brazing lamp can be 
recommended. With this lamp, of course, the bellows 
is not used, and only an iron hearth with asbestos cubes 
is wanted ; but gas should be used if available. 

The Method.— For satisfactory brazing, thoroughly 



92 SOLDERING, BRAZING AND WELDING 

clean the surfaces to be joined, first with a file and then 
with emery-cloth, and, if necessary, bind them together 
with thin iron wire. A flux of borax and water mixed 
up into a thick paste is smeared round the joint, which 
should then be warmed to get rid of the moisture. 
Heat the metal to a white heat , dip the spelter into 
the borax paste, and apply to the part to be joined, 
rubbing round the joint until the brass is seen to run, 
when the heat can be cut off. The work should be 
almost covered in the asbestos cubes, and the spelter 
applied all round and not only in one place ; failures to 
unite the parts mostly result from insufficient heat or 
cleaning of the parts. 

Brazing-lamps. — These lamps are constructed to 
burn benzoline or paraffin, and the more powerful 
types are fitted with pumps so that air pressure may 
be exerted on the oil. The paraffin or benzoline is 
thus forced into the burner, and by passing through 
the previously heated tubular coil is converted into gas, 
which issues forth out of the gas nipple, mixes with 
air, and then burns with a blue atmospheric flame of 
high temperature. After filling the lamp, a torch 
should be held under the burner to vaporise the oil, 
and thus ignite the lamp, after which pressure is 
applied by means of the pump. Do not start pumping 
too soon — that is, before the burner is sufficiently hot 
to vaporise the oil— or the oil itself will be forced 
through the gas nipple. The flame may be regulated 
at will, to suit the work in hand, after the burner has 
become thoroughly hot to set the lamp fairly going. 



BRAZING 93 



When brazing, lay the article to be brazed on some 
broken coke, charcoal, or firebrick, and if the article is 
comparatively heavy, cover it over with some small 
pieces (to conserve the heat) except where the brazing 
is required. After applying flux and spelter to the 
previously cleaned metal, direct the flame of the lamp 
on it, gently at first, until the spelter fuses and makes 
the joint. 

Gas Blowpipe for Brazing. —Brazing blowpipes 
should be fitted with a combination air and gas 
regulator, by means of which both the size and nature 
of the flame can be adjusted to suit the work in hand*. 
When choosing a blowpipe it is always better to make 
one rather larger than the work in hand necessitates — 
the flame can be reduced when required ; by this 
means a margin of reserve is provided which is useful 
in emergencies. A blowpipe whose dimensions are 
10 in. long, having a f-in. gas supply reduced to -^ in. 
at the nozzle, and a f-in. air supply reduced to -tq in. 
at the nozzle, will braze ordinary latch keys and other 
similar work if used with a No. 3 size blower. As 
already stated, a paraffin, petrol or benzoline blowlamp 
is a cheap and effective apparatus, especially where 
the quantity of work to be done does not warrant 
the outlay of a foot blower, gas blowpipe, etc., 
but gas lias advantages over the liquid fuel, in- 
asmuch as the blowpipe is more under control. 
The quantities of gas and air can be readily and 
more delicately adjusted during the actual brazing 
process, then as soon as the spelter fuses and the 



94 SOLDERING, BRAZING AND WELDING 

gas is turned off, the stream of cold air soon counter- 
acts any excessive heat. 

Making a Gas Brazing Hearth. — The brazing 
hearth can be bought ready-made, or can be cheaply 
put together by the worker himself, the necessary 
materials consisting of two bellows, some lead piping, 
and an old packing case to support a large size frying- 
pan — about 1 ft. 4 in. by 1 ft. The bellows are fixed 
one above the other, interconnected by a fixed lead 
pipe, one pair of bellows worked by the foot pumping 
air into the pair above it, from which the air is taken 
to a bunsen blast burner by flexible tube. This bunsen 
burner can also be easily and cheaply made, and as this 
works very well and will be found useful for both 
soldering and brazing, the following hints on making 
it are given. First, get two ordinary large house 
bellows about 1 ft. square, or larger if possible; the 
larger the better. Next a good strong packing case 
about 2 ft. long by 1 ft. 3 in. high and 10 in. wide is 
required. One end of the box will form the base, and 
to make it steadier two 1-in. boards should be screwed 
across to protrude about 6 in. on each side, the front 
one being considerably wider, as can be seen at t (Pig. 
62), which shows the apparatus with one of the case 
sides removed. The packing case proper is denoted by 
the letter A ; the part A s A was formerly the bottom 
of the case, but is now the back ; and the top a v a was 
the end of the packing case. Half-way between the 
top and bottom a shelf b should be fixed, having a 
large hole cut out of the middle at g to accommodate 



BRAZING 



95 



the. union piece (seen in section) , which holds the lead 
air-pipe communicating from the lower bellows to the 
upper. 

In the back, near the bottom, at s, cut a hole for 
the nozzle of one of the bellows, and above the shelf 




Fig. 62. — Home-made Brazing Hearth 

cut another hole at s 1 to take the nozzle of the other 
bellows. The bottom bellows c should have the top 
handle extended by a piece of stout bent iron n to act 
as a pedal, and should be screwed to the base. A 
central hole about 3 in. in diameter should be cut at p 
to allow the air to reach the valve. Now get a piece of 
lead pipe J in. inside diameter, and, having cut down 
the nozzle to just under that diameter, force the mouth 



96 SOLDERING, BRAZING AND WELDING 

of the pipe over it as at s, and bend the pipe F as 
shown, to reach the centre of the shelf b and enter the 
hole G until flush with the top. Kemove the lead pipe 
and get a block of wood about 3 in. square. Cut off 
the corners and bore a hole in the middle, so that the 
lead pipe will just pass through it, and countersink the 
hole. Broach out the mouth of the lead pipe until it 
becomes bell-shaped and fits the block of wood, so that 
its edge is flush with the wood when pressed hard 
against it. This is clearly shown at G, where the dark 
shading represents the wood block. Cut a leather 
washer the size of the block, with a J-in. central hole, 
and lay this over the hole in the bottom of the top 
bellows where the leather flap valve is. Bore two 
holes in the wood block, and screw this down tightly 
to the bottom of the bellows, so that the bell-mouth of 
the lead pipe faces the hole and has the leather between 
it and the block. This should make an air-tight joint 
for the fixing of the pipe to the bellows. 

Next, push the nozzle of the bellows through the 
hole s 1 , and screw the bellows down tightly to the shelf 
b. Join the lead pipe to the nozzle of the bottom 
bellows, and make an air-tight joint with glue and 
tape bound round. Between the top of the upper 
bellows d and the top of the packing case at v, a stout 
sofa spring E is fixed to keep the top bellows shut down 
tight till air is pumped in from the bellows below. 

From a screw near the top of the case stretch a 
house-bell coil spring m, and attach its lower end to 
the foot-plate or pedal n. This spring tends to keep 



BRAZING 97 



the lower bellows open. When pressure is put on the 
foot-plate N, air is pumped from the lower to the upper 
bellows, and thence along the flexible pipe e to the 
bunsen blast nozzle described in detail later. If it were 
not for the upper bellows, the air would come to the 
nozzle in puffs, but the spring e keeps the pressure 
constant, and a steady blast is secured. The rubber 
pipe R should be of sufficient length to reach the hand 
conveniently, and allow room for movement. 

The hearth K can be made from sheet-metal, with 
the edges bent upwards to form a tray ; or an old frying- 
pan will answer very well. Whichever is employed, 
four iron stays or legs h must be used to raise it above 
the top of the packing case as shown. These legs 
should be screwed at one end to the sides of the case, 
and at the other to the pan, and if a frying-pan is used, 
the handle may be cut and bent to form a hook as at 
L ; it then acts as a support for the blast nozzle. 

For use with the brazing hearth, a blast gas nozzle 
on the bunsen principle is required, and this is easily 
made from two pieces of gas-piping, a right-angle 
joint, and two mouthpieces to take flexible pipes. 
First, get 1 ft. of f-in. brass (or iron) pipe and an 
elbow, internally threaded at both ends. Cut 2 in. off 
the brass pipe, and cut a thread at one end of the short 
piece and one end of the long piece, to screw into the 
elbow as shown in Fig. 03. At the other end of the 
long tube solder in a cock or mouthpiece to take a large 
din meter flexible pipe from the gas bracket. Next get 
1 ft. of J-in. brass pipe, and bend it to the shape shown 

H 



98 SOLDERING, BRAZING AND WELDING 

at b, soldering a mouthpiece at F to take the smaller 
diameter air-pipe K (Fig. 62) from the bellows. Bore 
a hole through the elbow c, and push the pipe in, 
making a tight fit, and so that it passes centrally 
through the larger brass tube until it nearly reaches 
the end as shown at d. Run a shoulder of solder to 
hold the small tube firmly in the larger one as at E, 
and unite with a drop of solder the large tube A and the 
small tube b where they cross at G. 

The gas passes up the large pipe, and out at D, and 
a blast of air is forced through the centre of the flame 
through the small pipe b. The shape of the small pipe 
allows~of it being readily hung up on the hook L (Fig. 
62) when not in use. Instead of the mouthpiece shown 
at H (Fig. 63), a cock will be found more convenient; 
but it should not be too small, or it will restrict the 
flow of gas, which should be as great as possible. No 
gas-cock should have less than J-in hole. 

The "fuel " (heat conservers) consists of chunks or 
cubes of asbestos, and when these are blown upon with 
the gas flame, the heat is quite sufficient for moderately 
heavy brazing. Be careful not to get any kinks in the 
flexible tubes, or the air and gas will be reduced in 
quantity, if not stopped altogether. 

A square of thick asbestos (sheet) is useful for lay- 
ing on small articles w T hilst brazing, and a piece or two 
of charcoal will be handy for silver-soldering. 

Brazing Iron and Steel.— Before attempting to 
braze either iron or steel the surfaces should be 
thoroughly cleaned by filing or grinding, etc. Brass or 



BRAZING 



99 



copper may be cleaned by dipping in a solution of 1 
part nitric acid and 2 parts of sulphuric acid. This 
same solution can be used to remove the scale after 
brazing. The parts should be fastened together in the 
position they are to occupy when joined. The fasten- 
ing may be effected by the use 
of wires, screws, bolts, clamps, 
etc. If practicable, the parts 
should be held in such a way 
that they can be turned over 
during the brazing process with- 
out disturbing the relation of the 
parts, thus affording a better 
chance to apply the flux and 
brazing material. 

In brazing sheet metal, if the 
seams are not required to stand 
much working after soldering, 
they may be joined edge to edge. 
When seams are formed in this 
way, little nicks, about J in. 
apart, should be filed out along 
the edges, so that the solder flowing through the 
nicks will render the joint sound. If the seam 
is to be worked after soldering, a small lap is 
necessary to ensure adequate strength. To form seams 
of this type, first thin the edge of the metal along the 
ends that are to form the seams, about J in. in from 
the edge, so that when the two edges are lapped over 
each other the combined thickness at the seams will be 




Fig. 63. — Blowpipe or 

Blast Gas Nozzle for 

Brazing Hearth 



ioo SOLDERING, BRAZING AND WELDING 

the same as the single thickness of the metal at other 
parts. Cut a small cramp at the top and bottom of the 
seam, and fit the opposite edge in these cramps. After 
preparing the seams by either of the above methods, 
fasten binding wire round the articles so as to hold 
the seams securely in position. Now powder some 
borax flux, mix equal parts of the borax paste and 
grains of spelter, and along the seams place sufficient 
of the mixture to solder them when melted. Some 
dry borax should also be kept ready at hand, so that 
a little may be taken and thrown on the solder at any 
point where the material does not appear to be flowing 
freely. Gently heat the article by some suitable 
means, such as foot bellows and blowpipe, so that it 
will expand equally, and not disarrange the seam ; in- 
crease the temperature until the metal is a dull red, 
and the spelter runs. If necessary, with a piece of 
wire flattened at one end gently rub the solder along 
the seam until every part is joined. 

Brazing Copper Rod. — For uniting two pieces of 
copper rod, \ in. or § in. in diameter, first prepare the 
joint as at A in Fig. 64, and file the surface of the 
copper clean in the immediate vicinity of the joint. A 
mixture of borax and water and spelter should now be 
applied to the joint, which should rest on a small heap 
of broken coke, the coke being also built round it. 
The flame of the blow-lamp should be directed at first 
on the coke surrounding the joint', and then gradually 
brought to bear on the joint itself. If necessary, add 
a little more spelter before any of it fuses, and when 



BRAZING 



101 



the copper begins to get red hot, throw just a pinch of 
dry borax on the joint to facilitate matters. 

Brazing Key Stems. — In brazing together the broken 
parts of a key stem, first it is necessary to file the 
fractured ends quite true ; this may entail the shorten- 
ing of the key by J in. or J in., and as another J in. 
will be lost in making the joint, it may be advisable 




Fig. 65. — Dovetailed Joint in Key Stem 

to use another key bow having a longer piece of stem 
than the one that was broken off. "With a warding 
file cut a dovetail on each of the ends to be joined, as 
shown by Fig. 65. A small, half-round file will assist 
in making the edges true and square. The pieces must 
interlock perfectly, and when this is the case, very 
lightly hammer the joint, round which then bind seven 
or eight turns of brass wire to act as spelter. Wet the 
joint, sprinkle powdered borax on it (this is to serve 
as the flux), and, holding the key in a pair of tongs, 
place it in a clear part of a forge fire made with 
charcoal, small coke, or coal cinders, and commence 



102 SOLDERING, BRAZING AND WELDING 

to blow steadily the forge bellows or blower. Failing 
a forge fire, use a blowpipe, the key being placed on a 
piece of charcoal or pumice-stone whilst the heat is 
being applied. If the forge fire is used it is as well to 
support the key on a guard of thick iron plate having 
a hole in its centre over which is the joint to be brazed. 
By this means the necessary local heating is obtained, 
and much labour in cleaning the key afterwards is 
avoided. On being heated, the borax swells and boils 
up, and should be pressed down with a spatula, pre- 
viously dipped in cold water to prevent the hot borax 
adhering to it ; a suitable spatula is made by flattening 
one end of a 1-ft. length of a J-in. round rod, having at 
its other end an eye by which it may be hung when not 
in use. With this spatula, also, powdered spelter may 
be added to the joint if required. When the brass wire 
begins to run, assist the flow by adding powdered 
borax, and when all the brass has run into the joint, 
rub off superfluous molten metal from underneath and 
allow the joint to cool gradually. When cold, file up 
and clean the stem of the key until only a thin bright 
line of brass can be seen. 

Cycle Brazing. — In cycle brazing , the first con- 
sideration is the means of heating the heaviest joint 
to a brazing heat. This may be done in several ways, 
by a paraffin blow-lamp costing at least 35s. to 40s., or, 
what is better, a gas blowpipe f in. or 1 in. in diameter, 
with at least J in. gas supply pipe and a fan or bellows 
to supply the necessary air pressure. A small fan is 
iar preferable to a bellows of any description, the flame 



BRAZING 103 



being steady and constant, and the operator being able 
to devote his entire attention to the job. In the 
absence of power, obtain a small circular double-blast 
bellows and hearth, costing with blowpipe about £5. 

The brazing materials are brass spelter, No. 3 size, 
or brass brazing wire and powdered borax ; a tin to 
hold the mixture of spelter and borax, and one for the 
plain borax ; a piece of iron wire about J in. by 18 in., 
flattened at one end to feed the spelter and borax to 
the joints; and a brazier's brush, which is desirable, 
but not absolutely necessary, to brush the superfluous 
borax and brass from the outside of the joint as soon as 
it is removed from the hearth ; this saves much work 
in filing up, and saves the files immensely. Do not 
purchase the borax ready powdered, but buy lump 
borax, as that purchased ready powdered is likely to be 
adulterated. In making the brazing mixture, use 
about equal parts, in bulk, of No. 3 spelter and borax. 

In preparing the work for brazing, see that the sur- 
faces are bright, clean, and free from scale. The joints 
should be a good tight fit, free from shake, and where 
a joint such as the back forks to the bridge lugs is 
being made, see that the tube edges fit close up to the 
shoulder of the lugs all round, and do not depend on 
the brass to fill up a badly fitted joint. 

The chief things to observe are to make a sound 
joint the full depth of the lug, and not merely to get a 
thin film of brass round the outer edge. To do this, 
the flame should be directed on to the thickest part of 
the lug first before getting the tube too hot, and feed- 



io 4 SOLDERING, BRAZING AND WELDING 

ing the joint with borax before the metals get hot 
enough to scale. As soon as the lug and tube begin to 
get a dull red, feed with borax only, then with brass 
and borax, when it should flow almost like water and 
penetrate to the deepest part of the joint. 

Another very important thing is not to "burn " the 
tube by getting it too hot, which will spoil it and cause 
an early fracture. If the above method of heating the 
lug first is observed, and the tube near the lug kept 
"wet" with borax to prevent it scaling, this should 
not happen o 

Where the joint to be brazed lends itself to inside 
loading with the spelter, the work should be so placed 
on the hearth that the brass inside, when it melts, will 
tend to flow to the outside of the joint. Then if borax 
only is used on the outside until brass appears round 
the edges, it will be fairly certain that a sound joint will 
result. As soon as this comes through, feed a little 
brass-and-borax mixture to the joint, and, as soon as 
this melts, stop the flame and remove from the hearth. 
If the flame is kept on too long after this, there is a 
possibility of "soaking " all the brass out of the joint, 
especially so if the joint is not a very good fit. 

Some braziers use a blacklead mixture for protect- 
ing thin tubes whilst brazing ; but care must be taken 
to keep it out of the actual joint, as brass will not 
adhere to metal where this is present. 

Cycle frame joints can be brazed on an ordinary 
smith's hearth, but it is rather risky, and requires more 
skill than with a gas blowpipe. It also requires a good 



BRA.ZING 105 



clear fire and a light blast. The job should be kept 
well fed with borax to prevent the tubes scaling and 
burning. The joint should be loaded from the inside 
with about a thimbleful or less of crushed borax and 
No. 3 spelter mixed in the proportion of about half of 
each in bulk. The heaviest part of the lug should be 
heated first, and the work must be turned frequently 
in the fire so as to avoid burning the tube. If the joint 
is fed from the outside with borax until the brass flows 
round it, a sound joint is ensured. This applies to a 
joint where the lug is fitted inside the tube. Where 
the tube is fitted inside the lug, a little brass and borax 
should be applied outside the joint just as the inside 
charge has melted, which can be seen with some joints 
by looking down the inside of the tube. When the 
tube is closed both ends, such as the last joint of a 
frame, the job is more difficult and requires careful 
judgment and skill to ensure a sound joint. 

Brazing Cast - iron. — Although it has been dog- 
matically asserted both that cast-iron can and cannot 
be brazed, it may be stated that the general results of 
attempting this process are so indifferent as to warrant 
the conclusion that this process cannot be recom- 
mended. In brazing, one of the conditions essential 
to success is that the metal to be brazed and the spelter 
should unite to form an alloy just where the brazing 
occurs, and that this should take place spontaneously. 
This actually happens when brazing copper, brass, 
wrought-iron, etc., but not in the case of cast-iron. 
If, however, the reader desires to experiment in this 



io6 SOLDERING, BRAZING AND WELDING 

direction, the following hints may be useful. First of 
all, remove all dirt and grease from the cast-iron, and 
then chemically clean it by immersion in hydrochloric 
acid, afterwards well rinsing it in clean cold water. A 
mixture of borax and water and spelter should now be 
applied where the brazing is required, and gentle heat 
then brought to bear on it until the water is evaporated. 
The heat should now be increased until the casting is 
red hot in the neighbourhood of the brazing ; and some 
workers claim that at this juncture the best results are 
obtained by dusting the red hot cast-iron liberally with 
boric or boracic acid powder. A hard spelter should 
be used in preference to a readily fusible one, other- 
wise the spelter would be fused much too soon, and 
before the casting is raised to a sufficiently high 
temperature. 

An experienced worker who believes that it is 
possible to make a sound joint in cast-iron by brazing, 
states that he has brazed articles with equal parts of 
borax and boracic acid. The chief difficulty is the flux. 
He has tried one called "Ferroment," which seems to 
give good results. The first casting brazed with it was 
3 in. wide and § in. thick, and this casting at the time 
of writing had been in w r ork six months for fifteen 
hours per day. This same worker prefers to roast 
borax before use, as it stops on the work better. Also, 
when a deep, wide joint is being dealt with, he finds it 
an advantage to smear on a little clay underneath and 
the side, as should the joint get slightly hotter in one 
part the spelter will run through and make an unsound 



BRAZING 107 



joint. The heat required to braze cast-iron varies 
somewhat with the spelter used. If brazing by means 
of a smithy fire, the spelter will show a blue flame 
when it starts to run, and the article must then be 
removed from the fire. In using a blowpipe or blow- 
lamp, the blue flame does not show, and one has to 
look for the spelter melting, and see that it flows well 
along the joint before removing the flame. Spelter 
which has been kept in stock a good time may not flow 
well. The worker in question prefers brazing wire to 
grain spelter, as by means of warming the end of the 
wire and dipping in the flux (which will adhere to the 
hot wire), it may be put just where desired. He 
collects all the soft brass turnings from his lathe and 
uses them for brazing. 

Another worker has stated that those who have a 
forge of any kind will find the following an effective 
method of repairing an iron casting. A flux may be 
made of chlorate of potash 4 oz., boracic acid 1 lb., 
and carbonate of iron 3 oz. These should be mixed 
well together and pounded. The parts to be brazed 
together should be carefully cleaned by scraping them, 
and brought to a bright-red heat. Then apply the flux 
and spelter and increase the heat. 

Still another worker says that in brazing cast-iron, 
if powdered soda is used instead of borax, the result 
will be a perfect joint. 



CHAPTEE XI 

Welding Iron and Steel under the Hammer 

Ikon and steel can be joined by heating until they be- 
come plastic and then consolidating the two members 
of the joint by hammer blows, the work being sup- 
ported on an anvil. Correct heat and cleanliness are 
the chief requisites. The " welding heat " corresponds 
with that temperature at which the metal is in a state 
of partial fusion on the surface. The better the quality 
of the iron, the higher the temperature it can stand 
without being burned and ruined. Iron at a welding 
heat gives off dazzling sparks, whereas ordinary cast 
steel is only an intense yellow, but few sparks being 
evolved. Sufficient lap for the proper making of the 
joint must always be allowed. When heated in a per- 
fectly clear fire, the metal may need no treatment 
prior to hammering ; but otherwise it may be necessary 
to sprinkle sand or some special flux over the work. At 
the proper moment the iron is transferred to the anvil, 
and the union of the two members of the joint imme- 
diately effected ; delay means an imperfect joint. In 
lifting the work out of the fire, remove it vertically 
and so as not to collect particles of dirt on it. Keep 
a switch of brushwood at hand for removing adhering 
matter. 

108 



WELDING IRON AND STEEL 109 

Welding of Steel Specially Considered. — Some 

steels will ' stand the fire ' better than others, 
which means that they will stand more heat before 
they reach the point when they begin to burn. 

The different kinds of steel used in a general way 
may be summed up as blister, spring, shear, double 
shear, and cast steel. Blister steel will, as a rule, stand 
the most heating before beginning to burn, and the 
others follow in the order given. The difference in 
heating will vary from nearly a white heat on blister 
to the yellow heat of cast steel. 

A simple method of ascertaining what heat a steel 
will stand before beginning to burn is as follows : Heat 
the steel to its burning point, and at various stages, 
beginning at the yellow stage, lay it on the anvil and 
give it a few blows with the hand hammer. Kepeat 
the process until a heat is reached that will cause the 
steel, when struck with the hammer, to give off sparks 
like small fireworks. When this stage is reached it 
will show that the burning point is arrived at. 

Careful observations of these points will enable the 
smith to know just when to begin to use the flux for 
welding, which, by the way, must be just before the 
steel reaches the burning point. 

Another important point is the formation of the 
scarfs. These should not be fullered down so thin or 
left in the same form as the scarfs as when joining iron, 
and should be shorter (compare a and b, Fig. 66). 

In bringing the steel up to its welding point, care 
must be taken to have it at a uniform heat throughout 



no SOLDERING, BRAZING AND WELDING 

at the part for welding; and, to get this, the blast 
should not be forced at the start, but used gently. In 
some cases the blast should be stopped occasionally, 
to allow the steel to soak. Then restart the blast, and 
gradually force it when beginning to use the flux, con- 
tinuing so until the welding point is reached. Only 
light blows should be given at the start, just to cause 
the two parts to stick together; but when stuck, the 
harder the blow the better the weld. 

An idea seems prevalent that the flux has a certain 
influence on the steel, and converts it into a form that 
makes it more weldable. The real use of a flux in this 
case is simply to retard the heat, and form a coat or 
shell on the steel, and so counteract and prevent the 
burning action w T hich takes place when heating steel 
in an ordinary blast fire. 

The reason why different fluxes are required for 
different brands of steel is no doubt due to the differ- 
ences in manufacture. As a rule, the greater the heat 
the steel will stand before burning, the less it requires 
a flux to protect it, so that in a great many cases a 
flux consisting of some clean, sharp sand is all that is 
required ; but the steels that will burn at a lower heat 
require something more than sand to protect them. 
Hence arises the necessity of adding burnt borax, 
crushed glass, powdered marble, etc. 

The method of welding steel is as follows ; but 
before proceeding to get the heat make a point of 
having a shallow tin on the forge large enough to hold 
a sufficient quantity of the flux, so that it will cover 



WELDING IRON AND STEEL in 

the scarfed end when being dipped in same, Have 
a clean fire and plenty of firing on the hearth, so that 
the heat can be well covered. Start with gentle blast 
until the heat is nearly up to burning point. If neces- 
sary, stop the blast and let the heat soak for a few 
seconds so as to ensure a uniform heat. Gradually 
force the blast, and keep withdrawing the "heats " and 
roll them well in the flux, and so continue until it is 
thought that the heat is plastic enough to unite. Place 
the scarfs in position, give a few light blows until the 
parts stick together, then hammer well home and move 





A B 

Fig. 66. — Scarfs for Iron and Steel 

smartly so as to ensure the proper joining together 
whilst in a plastic state. When welded, do not con- 
tinue the hammering or tooling at too low a heat ; but 
if further hammering is necessary, re-heat the work. 

These hints are not applicable to every make of 
steel. With the special steels manufacturers issue par- 
ticular instructions. 

A flux for welding cast steel consists of 2 oz. each 
of powdered chalk, soda and burnt borax, mixed with 
1 lb. of silver sand. 

A firm of steel manufacturers recommend a mix- 
ture of 21 oz. of sand and 7 oz. of salt, moistened ; the 
steel is to be treated in a fire of sulphurless coal. 



CHAPTEE XII 
Making Blowpipes 

How to Make a Bench Gas Blowpipe. — The blow- 
pipe illustrated by Fig. 67 gives a powerful flame. 
It can be clamped to the edge of the workbench by 
means of a winged nut, a hole being made near the 
edge of the bench to accommodate the bolt. A piece 
of hard wood A, 5 in. by 2 in. by 1 in. thick, has a 
strong iron bolt B passed through at one end. A 2-in. 
cube c, which should also be of good hard wood, is 
screwed firmly to the other end of A, the combined 
block being perforated through the centre to take a 
length of gas tube D, which carries a gas-bracket with 
flange, elbow joint, and tap E. The flange should be 
screwed down to the top of the block. The elbow joint 
allows the direction of the flame to be adjusted within 
a wide range movement. The arm of the bracket is 
removed, and a shorter tube F, 3 in. long, is substi- 
tuted. This carries a J-in. iron T- piece G. The tube 
H, which is 3 in. long, should be of brass, threaded at 
one end to fit into the T. 

The air is conveyed through an 8-in. brass tube J 
J in. in diameter, which should be smooth inside. This 
latter point is of some importance, and, if preferred, 
a glass tube may be used instead of brass, the current 
of cold air having a sufficient cooling effect to prevent 



MAKING BLOWPIPES 113 

undue heating. The end should be cut off sharp with 
a file in the ordinary way and left in that condition. 
Smoothing the edge by fusion in a flame will not im- 
prove matters, but rather the reverse. Of course, the 
other end, which comes outside, must be smoothed to 
prevent injury to the indiarubber tube used for making 
connection with the bellows. The air tube must be 
held firmly in the centre of the gas tube, while capable 
of being moved in or out for the purpose of adjusting 
the flame. This can be done quite satisfactorily by 
means of a short brass tube or nipple K, threaded to 
screw into the T (see Fig. 67). A sound cork should 
be driven into this short tube so as to entirely fill it, 
a hole being made with a cork-borer to admit the air 
tube. This hole must be exactly central, and the cork 
must grip rather tightly. 

A foot-bellows is generally used for supplying the 
air, the bellows being connected with the air jet J by 
means of an indiarubber tube. The tube d, which 
should extend an inch or so below the bench, is to be 
connected with the gas supply. 

A Simple Gas Blowpipe.— A simple form of gas 
blowpipe is shown in Fig. 68, the rubber tube con- 
necting it with the gas supply being fixed on the pipe 
at the point of connection with the cock. To construct 
the appliance, one end of a piece of brass gas pipe 
of the required length with, say, a §-in. bore, is bent 
as shown, whilst at the back of the curve thus made a 
hole is drilled to admit a tube A -3^- in. in diameter. 
This should have one end (see dotted lines) bent to 



ii4 SOLDERING, BRAZING AND WELDING 

correspond with the angle previously formed in the 
larger tube, whilst its other extremity should be bent 
upwards. Make these pipes red hot where they are to 
be bent, and, if they are afterwards plunged in cold 
water, the material will to some extent be softened, 
and its tendency to split will be obviated. The smaller 
tube is passed through the hole in the bend of the 
larger one, the ends being almost flush and quite con- 
centric. Solder the parallel portions of the tubes to- 
gether, and then fix a gas-regulating cock to the larger 
one, as in Fig. 68. The end is then connected to an 
ordinary bracket or burner by means of an indiarubber 
tube G, and a short piece of tubing is fitted with a bone 
or other mouthpiece, and attached to the projecting end 
of {he air tube. This instrument will do any soldering, 
and will be suitable for melting gold, silver, and brass, 
or brazing odd jobs in iron or steel. Of course, when 
used for the last-named purpose it would be in con- 
junction with asbestos tubes or other supports. 

Proportion of Air to Gas.— As regards the relative 
volumes of gas and air for blowpipes, the late Mr. 
Thomas Fletcher said that, speaking roughly, but still 
sufficiently near to make a correct rule by which to 
work, a blowpipe requires one volume of gas to eight 
of air. If the gas is supplied at a pressure equal to 
1 in. of water, and the air at eight times that pressure, 
then, to get the best effect, the area of the gas and air 
pipes should be equal. If the air supply is equal to 
16 in. of water pressure, the gas pipe must be double 
the area of the air, and so on in proportion. Some 



n6 SOLDERING, BRAZING AND WELDING 

makers assert that a better working flame is produced 
by using ten volumes of air to one volume of gas ; but, 
of course, if the blowpipe is fitted with taps, the sup- 
plies can be adjusted easily. It will be found, however, 
that any practical departure from Fletcher's rule will 
result in a loss of power. 

Capacities of Blowpipes.— It has been said, a blow- 
pipe with a |-in. air jet, if worked with an air pressure 
of 10 oz. per square inch — that is, 15 in. of water — 
will braze up to about J lb. total weight ; or in other 
words, will securely unite two pieces of brass each 
weighing J lb. With the same pressure a J-im bore 
air-jet will braze a total weight of about 2 lb., and so 
on in proportion. It will be understood that the air 
jet is measured at the point at which the blast leaves 
the air tube, whilst the area of the gas supply is that 
of the annular space between the two tubes. When 
the air tube is thus carried inside the gas tube (sec 
Fig. 69), the tool appears to be much larger than it 
really is, and this accounts for the fact that a |-in. 
size blowpipe with the air tube fixed outside the gas 
supply is just as effective as one of the f-in. size which 
carry the air tube inside the stem. All indiarubber 
tubing must be perfectly smooth inside, for if it is 
wired or in any way rough, the resultant friction will 
cause a loss of pressure. It should also be of as large 
a bore as is convenient. 

Large and Efficient Blowpipe.— A large and effi- 
cient blowpipe that can be made in a few minutes is 
shown by Fig. 69, the only materials required being 



MAKING BLOWPIPES 117 

a T-coupling and diminishing socket, an elbow, and 
one or two pieces of pipe. The air tube A (represented 
for the most part by dotted lines) passes through the 
diminishing socket until it almost reaches the nozzle 
of the blowpipe, with which it is concentric. By using 
the elbow d, the two supply pipes are brought parallel 
to each other, so that the indiarubber connecting tubes 
can be more easily held in the hand like reins, as by 
simply squeezing them the flame can be readily regu- 
lated. Sometimes, in cases of emergency, a plug 
drilled to meet the air tube is used in place of the 
socket. The plug is thrust into the end of the T-socket ; 
but in all cases it must be airtight. This blowpipe can 
be used efficiently only in conjunction with a foot 
blower. 



CHAPTEE XIII 

Managing Blow-lamps 

The stoves and lamps burning paraffin in the form of 
vapour have become very popular on account of their 
good heating properties, portability, and little attention 
required. They consist of a container holding paraffin, 
a burner with a heating tube attached is screwed to 
the container, and a tube leading almost to the bottom. 
A small air-tube, similar to a cycle-pump, is fixed in 
container, the handle and cap only being in sight. 
When the burner tubes are heated, a thumbscrew on 
the filler caps is closed, and a few strokes of the pump 
puts a slight pressure on the oil in the container. The 
oil is forced up the central tube to the burner; but 
before reaching this it has to flow round the heating 
coils, and in so doing is turned to vapour. The outlet 
at the nipple being very small, causes the vapour to 
issue with some force, and it mixes with the air, form- 
ing a mixture which burns with a non-luminous flame 
similar to that of a bunsen burner. This flame plays 
on the heating coils, and once started, the lamp is 
practically automatic ; a stroke or two from the pump 
will keep it going until the oil is consumed. 

There are patterns that use petrol or benzol, their 
action being slightly different > Petrol and benzol are 

light spirits, which give off inflammable vapour at a 

11S 



MANAGING BLOW-LAMPS 119 



much lower heat than paraffin does. Advantage is 
taken of this fact by causing burner and nipple to be 
in one solid brass casting, so that when the nozzle is 
heated, the brass conducts the heat back to the nipple 
and so vaporises the petrol, which is fed to the nipple 
by a thick wick contained in a tube which reaches 
almost to the bottom of the container, the wick touch- 
ing the bottom. 

To start either paraffin or petrol lamps, the exit tube 
or nozzle is heated. The petrol lamp has no coils round 
the nozzle ; but comes straight from the holder to the 
exit nipple. The size of flame is regulated by a needle 
valve fitted with a wood or fibre handle. The petrol 
lamp has no pump, except on high-power brazing 
lamps whose use requires expert handling. 

The chief trouble with lamps using paraffin is that 
the burner becomes choked ; this is shown by the lamp 
jumping out or the flame not attaining sufficient heat. 
The makers supply a proper cleaning needle, a sheet 
stamped to form a handle and a piece of fine steel wire 
fixed at one end 4 . Nothing else, such as pins, etc., 
should be used, or the hole in the hippie becomes en- 
larged, and emitting too much gas, causes a smoky 
flame. The cleaner should be used each time before 
lighting. A good way to avoid this trouble is to use 
a small funnel with fine brass gauze soldered in the 
body when filling. White Eose is a quite satisfactory 
oil for these lamps. 

After considerable use the heating coil becomes 
choked with carbon deposit. A new heater tube can 



i2o SOLDERING, BRAZING AND WELDING 

be obtained, or the old one cleaned by drilling two or 
three holes in the ends and passing a piece of flexible 
wire (such as Bowden brake wire) through the heater 
and removing the obstruction. After getting it clean, 
tap out the holes and fix suitable screws, flat under 
the head, with a piece of asbestos to make a tight joint. 

If a larger flame is not obtained by pumping, take 
the cap off the pump and draw out the plunger ; the 
leather is probably worn. Fit a new one ; or it may 
have become hard, in which case apply a little oil and 
open out carefully. The retaining valve is in the 
centre of the pump bottom, and is removed by using 
a long key down the pump barrel. The valve is in four 
pieces. See that the spring is free and that the cork 
is in good condition. When replacing, take care not 
to get it cross thread, and screw firmly home. The 
washer under the filler cap is of rubber and cuts 
through in time. Do not use pliers to screw down ; it 
will go gas-tight with the fingers if the washer is good. 

To remove the nipple from which the gas issues is 
almost impossible without a proper key. This has a 
universal joint, which allows it to be rotated, although 
the handle is almost at right angles with the burner. 
Keys and all other parts mentioned can be obtained 
from any dealer in these lamps. 

With the lamps using petrol, the only parts re- 
quiring attention are the plate from which gas issues 
and the wick. Unlike the paraffin nipple, this is a 
circular stamping of brass approximately § in. in 
diameter with a fine hole in the centre. To remove 



MANAGING BLOW-LAMPS 121 

this disc, pass a long fiat screwdriver blade through 
two openings in the nozzle and turn to the left (anti- 
clockwise) , holding the body of the lamp firmly on the 
bench. Before fitting a new disc, thoroughly clean 
recess and remove any deposit from the inside of the 
valve box. Unscrew the needle and gland if there is 
any leak there, and clean and repack with asbestos 
yarn. A little glycerine on the packing appears to be 
an advantage. Place the disc in position, dip an 
asbestos washer in water, and screw the nozzle firmly 
down. 

The wick inside the lamp filters the spirit before 
reaching the nipple and occasionally needs replacing. 
Remove the cap from the bottom of the lamp, and with 
a piece of thick wire flattened at one end and filed to 
a hook, push it up the tube and withdraw the old wick. 
The new one is simply put in its place and the cap 
screwed tight. The washer under the filled cap is of 
cork and rarely gives any trouble. 



CHAPTEE XIV 
Making Blow-lamps 

A Paraffin Brazing Blow-lamp— The brazing blow- 
lamp shown in Fig. 70 was made at a total cost of 
less than 4s. The illustration is printed to a scale of 
about one-quarter full size. The lamp illustrated is 
not a mere experiment, as the writer of this description 
had a similar one in use for over two years, and during 
that time brazed hundreds of jobs with its aid. 

The container is of tinplate, and adapted from a 
workman's tea can. When purchased this will have 
a wire handle and two hinges, and these should be re- 
moved and soldered up. The handle shown at H is made 
from a strip of iron, J-in. by f-in. section, bent round 
to the shape shown and riveted to the side of the con- 
tainer. These rivets should be well soldered over in- 
side to prevent leakage. The joint of the longer strip 
is shown at x. The lid should next be taken in hand, 
a T%--in. hole being drilled at one side close to the 
handle, to take an ordinary Lucas cycle valve. A 
leather washer is fitted inside, and also one outside 
under the lock nut, the latter being then tightly 
clamped up. 

At E is shown the filling cap, the body part of which 
was taken from an old paraffin oil-lamp container, and 
the screw cap made at the local brass works ; but this 

122 



MAKING BLOW-LAMPS 



123 



fitting can be obtained in a finished state from many 
model-fittings manufacturers. This is soldered to the 
lid in the position shown, a hole being afterwards 
drilled in the tin to suit it. 

The cock shown at d is an ordinary gas-cock, with 
a length of f-in. outside-diameter copper piping screwed 



Fig. 70. — Paraffin 
Brazing Blow-lamp, 
the container being 
shown in section 




and sweated in beneath. This is passed through a hole 
drilled in the lid for its reception, and the base of the 
cock is then sweated in position. Note that the length 
of this pipe is such that when the lid is in place it 
clears the container bottom by J in. 

The coil of piping at P is § in. diameter copper tube 



124 SOLDERING, BRAZING AND WELDING 

coiled round to the shape shown, the lower end being 
tightly screwed into the top of the cock. The opposite 
end is screwed for a short length of f-in. gas thread, 
and very tightly fitted with a screw plug such as that 
used by plumbers for shutting off a portion of gas 
piping. Before screwing this on, a small hole about 
g 1 ^ in. in diameter should be drilled in the middle of 
same ; this is the nipple for the exit of gas to the 
burner. 

The f-in. copper tubing should not require filling 
with anything before bending ; this operation is best 
done round a mandrel of wood. No heating is neces- 
sary. A certain amount of flattening of the tube will 
no doubt occur, but this is immaterial. The end of the 
flame tube is, of course, open, otherwise the flame could 
not emerge. The nipple end of the flame tube is also 
quite open, with the nipple end of the coil just pro- 
jecting inside. The portion of tubing shown dotted in 
Fig. 70 takes the vapour from the coils to the nipple; 
it does not pass through the coils, but at the back of 
them, and bends round as shown. 

The lid of the container should now be carefully 
soldered down all round, and then the i^-in. brass stay 
rod shown at s must be fitted and both ends sweated 
over. It is essential that this stay is not omitted, as 
otherwise the pressure to which the container is sub- 
jected would bulge out the ends. 

The flame tube a should now be made of ^-in, 
sheet-iron, being held in place by two or three clips 
riveted on and bent over the coil ends, as shown at c. 



MAKING BLOW-LAMPS 125 

only one of which is shown for clearness. The flame 
tube does not taper, nor is the back end closed up. Its 
diameter should be 1J in. and length 3 J in., but this 
depends on the size of the hole in the nipple. No 
holes are required in this tube, as all the air is drawn 
in at the end. The nipple has a gas thread cut inside 
it, and it is screwed tightly on to the end of the copper 
coil. The length of the pipe from tap to coil is not 
important ; about 9 in. will be satisfactory. 

The best means of joining the nipple to the tube 
is to screw the end of the tube before bending it round 
at the end, and then to screw the nipple on tightly. 
The pipe can afterwards be bent as shown. 

The jet hole in the nipple should be about o 1 ^ in. 
bare, and should be so drilled that the issuing gas passes 
through the centre of the flame tubes. The tube is 
open at both ends, to allow air to be drawn down and 
complete the combustion of the paraffin vapour, the 
mixture igniting and burning properly when the 
vapour passes out at the other end and comes into con- 
tact with the atmosphere. 

To use the lamp, it should be filled about two-thirds 
or one-half full of paraffin oil, and the container cap 
then screwed hard down with a leather cap as a washer. 
A cycle pump should then be connected to the valve v, 
and a few strokes given, the cock d being meanwhile 
closed. The copper coil should next be put into a 
gas flame or the fire for a few minutes until nearly red 
hot, and then the cock D should be opened a shade, 
which will allow the paraffin to rise up the pipe 1 and 



i26 SOLDERING, BRAZING AND WELDING 

enter the coils P, where it will become vaporised, and 
the gas will then issue from the nozzle N, and burn at 
the mouth of the coils. 

The lamp may then be applied to the job, and five 
or six more strokes given to the pump, when the 
flame should burn with an intense heat and give out a 
roaring noise. 

The theory of action of lamps of this character is 
as follows : The pressure of air in the container forces 
the paraffin up the copper tube into the coil, where 
it is vaporised by the red-hot piping. The vapour then 
issues at some pressure from the nipple hole and, pass- 
ing down the flame tube, an ejector action is caused 
which draws air in with it. This air mingles with the 
paraffin vapour, and when the mixture issues at the 
other end, and comes into contact with more air, com- 
bustion takes place. 

The heat produced by the lamp should be quite suffi- 
cient to braze the bottom bracket of a motor-cycle 
frame and other similar jobs. The size of nipple with 
relation to the size of the flame tube is most important. 
If the flame tube be too large in proportion, the result 
is an excess of air, which cools the gas unduly and the 
flame dies out. A candle is put out in a draught from 
the same cause. On the other hand, if the flame tube 
is too small, or the nipple hole too large, the result is 
an excess of gas, causing incomplete combustion and a 
partly luminous and smoky flame, with less heating 
power. To ascertain if the nipple hole is too small, 
take a strip of tin and, whilst the lamp is burning, hold 



MAKING BLOW-LAMPS 127 

the tin partly over the end of the flame tube, so as to 
restrict the amount of air entering, and note the result. 

If the drawing (Fig. 70) be regarded as 4 in. to 
1 ft., and the lamp made accordingly, it will be of 
ample size to braze small and model boilers. It must 
be understood, though, that the size of the lamp alone 
does not govern the size of the flame, this depending 
entirely on, firstly, the size of the nipple, and secondly, 
the pressure of air in the container forcing the vapour 
out. The larger the container, the longer the lamp 
will burn without refilling, and, incidentally, the larger 
it is the weaker the container will be, and vice versa. 

Should this lamp be required for brazing and silver- 
soldering articles about J in. in diameter, it must be 
altered, as it is obviously much too large. The same 
container will do, of course, although perhaps rather 
unwieldy. If preferred, another container just half the 
size could be made ; this will be handier in use, although 
it will not allow the lamp to burn for so long a period 
without recharging as the larger pattern. For the 
tubing, i%--in. copper tube, preferably solid drawn, will 
be suitable. This should be heated to a dull red and 
then quenched in water to anneal it, this making the 
task of bending it much simpler. If it kinks too much 
in the bent portions, pour some molten resin into the 
tube, one end being plugged up for this purpose, and 
when set, bend to the shape desired. The resin can be 
heated and run out afterwards. The flame tube may 
be half the diameter and length of the one illustrated, 
but no hard and fast rule can be given for the dimen- 



128 SOLDERING, BRAZING AND WELDING 

sions of this part of the lamp, as the size of the nipple 
hole has everything to do with this. Make the latter 
just big enough to admit a fine needle. A simple 
method is to drill the cap almost through, and then 
punch the rest through with the point of a needle. By 
experimenting, it will be easy to find the right propor- 
tions of flame tuBe and nipple hole. The screwed joints 
should be a metal-to-metal fit as it is termed, that is, 
they should fit so tightly when screwed home that no 
leakage is possible. This can be ensured by seeing that 
all male threads are a tight fit in their respective holes. 



CHAPTER XV 
Electric and Thermit Welding Briefly Considered 

Contact Welding, — The electric welding of iron 
strips and sheets is usually done by the Thomson pro- 
cess of " contact-welding." In this process the metal 
is brought to a welding heat by passing a very large 
current through the joint to be welded, which, by 
virtue of its high resistance in relation to other parts 
of the circuit, develops great local heat. When the 
correct temperature for welding is reached, the joint is 
pressed together by mechanical means, and the current 
interrupted. In Fig. 71 the necessary arrangements 
for the welding of a steel rim are sketched. A is the 
iron core of an alternating current transformer and b 
the primary winding supplied w T ith alternating current 
either from a works dynamo or a public supply, and 
controlled by a double-pole switch c. The transformer 
has a secondary winding consisting of a single copper 
strip of very heavy section D, in which secondary cur- 
rents of low voltage but very large volume are induced. 
This winding d terminates in two heavy metal clamps 
E, one fixed and the other capable of movement by 
rack and pinion or screw, and the clamps must be 
shaped to the contours of the work F they are intended 
to hold, so as to fit well and present as little electrical 
resistance there as possible. The butt ends of the 

J 129 



i3o SOLDERING, BRAZING AND WELDING 

wheel rim are brought into contact, current switched 
on at the transformer primary, and immediately a very 
heavy secondary current passes round the ' ' winding 
d , generating intense heat at the junction of the metal 
rim g held in the clamps, where the electrical resist- 
ance is comparatively high. In a few moments the 
joint will arrive at welding heat and the screw feed is 
then operated, driving the joint together and complet- 
ing the weld, except so far as a little hand dressing may 
be found necessary. Directly the weld is established 
the current is switched off at the mains and the job 
allowed to cool out. Nothing less than 5 kilowatts to 
10 kilowatts is likely to be very satisfactory for hoops 
about | in. by No. 16 gauge, and the current must be 
alternating. The primary voltage and frequency is 
immaterial, as the transformer can be wound to suit 
the circuit conditions whatever they may be. 

The method of welding by resistance, that is, by 
raising locally the welding point to the temperature 
required by bringing the two surfaces into contact until 
their high resistance produces a welding heat and then 
squeezing them together, is by far the most manage- 
able and satisfactory commercial process of the two 
electrical processes. It is adapted for " spot-welding ' 
or producing local adhesions between metal plates after 
the manner of riveting, for butt or end-on welds, for 
seams, chains, rings, etc., and automatic welding 
machines are now made that can deal with no less than 
1,500 welds and upwards per hour with semi-skilled 
labour , with the least possible percentage of failures 



ELECTRIC AND THERMIT WELDING 131 



and a very low cost for electrical energy. Alternating- 
current is essential with this type of weld, and is used 
to energise a step-down transformer of special construc- 
tion. 

Arc Welding. — Notwithstanding the superiority of 
the resistance welding process to most commercial 
work, particularly that of a small 
kind necessitating rapid repeat 
work, the "arc" method, which 
has been in use for many years, 
and was probably the first ex- 
perimented with, has now become 
largely used on work where it was 
thought impossible to adapt it a 
few years ago. The system is 
extensively employed in iron and 
steel works, shipyards, and boiler 
works, and the class of work it is 
employed on varies from the dis- 
mantling of iron and steel build- 
ings, by fusing and cutting 
through the structural ironwork 
and girders, to the filling up of blowholes in castings. 
The metal to be welded is connected to one pole, and 
the electrode handled by the operator forms the other 
pole, an arc being struck between the two. Broken 
castings and forgings can be satisfactorily repaired by 
running new fused metal round them. 

Eecently the arc system has been applied with suc- 
cess for making welds on tramway rails, the resistance 




r I 

Fig. 71.— Electric Con- 
tact Welding of Steel Rim 



i32 SOLDERING, BRAZING AND WELDING 

of the welded joint being found very much lower than 
when made with the usual fishplates and bonded joints. 
Continuous current gives better results than alternating 
for the arc system, and a generator designed for use with 
this process has a " drooping characteristic," that is, 
the volts at the terminals fall rapidly with an increase 
in the current output. In this way the current is auto- 
matically limited to some extent, when the short- 
circuiting effect of the operation comes into play. Suc- 
cessfully to weld by this process a current of 300 to 500 
amperes at 80 volts is necessary, and every precaution 
has to be taken to protect the workman from the in- 
tense glare of the arc. 

Thermit. — Thermit is an aluminium alloy whose 
combustion generates so much heat that the substance 
can be used for the welding of iron and steel. It is 
the patented invention of Dr. Hans Goldschmidt. With 
thermit as a means of melting and welding, and with 
the use of special clamps and devices, a number of 
operations, otherwise difficult, can be performed, and 
thermit has come into general use for repairing broken 
or defective parts. By the use of a portable jacket and 
clamp, the joints of gas, w^ater, and steam pipes may 
be welded with the pipes in position ; and the advan- 
tages of such a material to an engineer far removed 
from supplies and repair shop, as at sea, can hardly 
be enumerated. New journals have been welded to 
heavy rolls, broken pump-rods have been joined, and 
a number of structural parts successfully united by 
its aid. 



ELECTRIC AND THERMIT WELDING 133 

Thermit is made up as follows : Iron oxide is inti- 
mately mixed up with about one-third as much in 
weight of powdered aluminium, according to the equa- 
tion Fe 2 3 2 A1-A1 2 3 2 Fe. The metals to be 
united are placed together and surrounded by a little 
clay or similar substance and the mixture is placed all 
around the joint. The mixture is fired by a little 
magnesium, and the chemical change that follows 
creates such an intense heat that iron is readily welded. 
When the joint is cold and cleaned up it is hardly 
perceptible. 

According to instructions published by Thermit, 
Ltd., it is of the utmost importance that the moulds, 
crucibles, etc., should be kept thoroughly dry, and they 
may advantageously be warmed before use to ensure 
the absence of any dampness. The parts to be welded 
must previously be brought to red heat, which is best 
effected by means of a gas and air flame. The proper 
design of the mould is of the utmost importance. It 
should have a runner and riser, and the metal should 
be allowed to flow between as well as around the ends 
of the pieces to be welded. The expense and incon- 
venience of making wooden patterns may be obviated 
by making the model of wax, ramming the sand round 
this, and subsequently melting out the wax. 



CHAPTEE XVI 

Oxy-Acetylene Welding 

Of late years oxy-acetylene welding and cutting have 
made great strides, and have placed at the disposal of 
the metal-working trades a means of doing many things 
that hitherto were impossible. Purified acetylene and 
oxygen, both under pressure, are supplied to a special 
blowpipe or torch. The flame in its hottest part has 
a temperature of about 4,000° C. and is therefore suffi- 
ciently high to melt any metals with which it may be 
brought into contact. The torch is fitted with all 
necessary adjustments to vary the supply of either of 
the gases, and constitutes a handy tool with which the 
intelligent worker soon acquires great dexterity. In 
a special form of the torch there is a means of intro- 
ducing a further supply of compressed oxygen, which 
makes it possible for the blowpipe flame to cut its 
way rapidly through thick metal, the particles of which 
are actually consumed in the path of the oxygen. 

It is out of the question in a single chapter of a 
handbook covering such a large scope as the present 
work to do more than indicate some of the uses to 
which the oxy-acetylene torch or blowpipe may be put. 
This chapter is obviously no attempt whatever at pro- 
viding a complete working guide to oxy-acetylene weld- 
ing. All that will be here attempted is to present a 

134 



OXY-AGETYLENE WELDING 135 

brief description of a typical outfit and some notes on 
working the blowpipe, and then to give some practical 
instruction from the pen of an oxy-acetylene welder on 
the treatment of copper, aluminium and cast-iron. It 
may here be pointed out that there is now a large 
number of firms specialising in the manufacture of oxy- 
acetylene welders' appliances, and most of them pub- 
lish illustrated catalogues which anyone proposing to 
equip himself for oxy-acetylene welding would do well 
to obtain. 

The source of the oxygen used in welding is now 
always cylinders, which are obtainable in various sizes, 
either by purchase or on hire from the gas-compressing 
companies, to whom they have to be returned for re- 
charging. The acetylene also can be had in the com- 
pressed form, but in this case the gas is not simply 
compressed into steel cylinders because, if it* were, any 
simple shock would be likely to cause explosion. The 
acetylene is therefore dissolved in liquid acetone, the 
cylinders containing some porous substance such as 
fossil meal, which is saturated with the acetone and 
the acetylene then pumped in. These also can be 
bought or hired from the gas-compressing companies. 
A tremendous amount of welding is done, however, 
with acetylene generated on the spot, and there are on 
the market quite a number of approved appliances that 
can be recommended, the best form of generator being 
that in which the calcium carbide is dropped into the 
water instead of the water dripping into the charge 
of calcium carbide. It is essential that the gas be 



136 SOLDERING, BRAZING AND WELDING 

purified before use. As most people doubtless know, 
acetylene is one of the hydro-carbon series of gases and 
is evolved by the action of water on calcium carbide, 
a substance which is one of the products of the electric 
furnace. 

The particulars and instructions on pp. 136 to 139 
are due to the Acetylene Corporation, Ltd. Fig. 72 
presents a diagrammatic illustration of a complete oxy- 
acetylene blowpipe equipment with the exception of the 
acetylene generator and holder, which apparatus may 
be placed in any suitable position (preferably outside) 
at any reasonable distance from the blowpipe, a is 
an ordinary gas tap connecting the hydraulic back pres- 
sure valve b with the acetylene supply pipe from the 
acetylene holder. The blowpipe is connected at valve 
c by means of a flexible tube with the outlet tap d 
of the hydraulic back-pressure valve. This forms the 
acetylene supply pipe to the blowpipe. The blowpipe 
is connected at valve e by means of a special canvas- 
covered strong rubber pipe with the outlet tap F of the 
oxygen pressure regulator, which is fixed, as shown, 
on the oxygen cylinder. G is a pressure gauge. This 
pipe conveys the oxygen supply to the blowpipe, and 
should be securely attached, as it is subject to pressures 
varying from 5 lb. to 40 lb. per sq. in. The hydraulic 
back-pressure valve should have been previously 
charged with water, and the gas regulator screwed into 
the oxygen cylinder. The blowpipe apparatus is now 
ready for use, with the taps A and d closed and the taps 
c, e and F open. 



OXY-AGETYLENE WELDING 



i37 



First, slowly open the oxygen cylinder valve (not 
shown) with the key supplied for that purpose. By 
means of the thumb-screw h, adjust the gas pressure 
to the correct working pressure for the blowpipe used. 
The approximate 



pres- 
sure of oxygen required 
for each blowpipe is as 
follows: No. 2, 8 lb. 
per sq. in. ; No. 3, 10 
lb. ; No. 4, 11 lb. ; No. 
5, 12 lb.; No. 6, 14 lb.; 
No. 7,. 16 lb.; No. 8, 
19 lb. ; No. 10, 20 lb. ; 
No. 12, 25 lb.; No. 15, 
30 lb. Then open the 
acetylene taps A and d, 
and when acetylene is 
unmistakably smelt at 
the nozzle of the blow- 
pipe, ignite the gases by 
means of a gas jet, 
candle, or taper. Then 
by means of the tap c 
slowly throttle down the 
acetylene until the small 
white cone of flame at 




Fig. 72. — Diagram of Oxy- 
acetylene Welding Apparatus 



the nozzle of the blowpipe shows a clearly defined out- 
line. As some indication of the correct size of the 
cone, it may be mentioned that when working with the 
No. 10 blowpipe this should be about J in. diameter by 



138 SOLDERING, BRAZING AND WELDING 

f in. long. This cone in the other blowpipes is 
greater or less according to the relative size. 

The tap a must never be used to regulate the supply 
of acetylene ; in fact, after the hydraulic back-pressure 
valve has been charged with water, it is best to leave 
this tap always on. 

The working pressure for oxygen previously given 
should not be too rigidly adhered to. Even in the same 
sizes of blowpipes the conditions must vary slightly , 
and a little practical experience with each blowpipe 
will soon indicate the best working conditions. If the 
flame is not properly regulated it may fire back and go 
out. If so, the taps c and e should be shut off at 
once, and a few seconds allowed to elapse before re- 
lighting. When work is carried on for a long time at 
a stretch and the burner becomes warm, it will be 
found necessary to slightly open the acetylene tap c 
from time to time. If work is being done which in- 
volves the nozzle of the blowpipe being held in a con- 
fined space, it is advantageous to cool this end of the 
blowpipe by immersing it from time to time in a bucket 
of water. While this is done the gases must be turned 
off at c and e. 

Welding should be done at the apex or outer ex- 
tremity of the small white cone. 

If the hole in the nozzle of the blowpipe gets 
obstructed at any time through beads of iron being 
splashed into it, or from any other cause, it may be 
cleared with a piece of copper wire and cleaned with a 
wire brush. No steel reamer or other sharp instrument 



OXY-ACETYLENE WELDING 139 

should be used in the hole, wfrich otherwise will be 
altered in size. 

On stopping work the acetylene tap c should be 
closed first and then the oxygen tap e. When work is 
completely stopped, the oxygen cylinder should be shut 
off. The oxygen cylinder valve should never be opened 
until taps f and e are open, and it should then be 
opened slowly. In this way sudden impact of oxygen 
in the regulator is obviated. 

The following instructions on the methods of weld- 
ing copper, cast-iron and aluminium are contributed by 
a foreman welder. 

Welding Copper.— Copper to be welded should have 
its edges bevelled to enable the welding to penetrate 
the entire thickness of the metal. Bevelling is not 
generally practised below a thickness of ^\ i n - From 
; f. y in. to tq in., a slight open bevel is sufficient ; -^q in. 
thick and over, the angle of the bevel should be about 
90°. It is not necessary to go beyond this even with 
great thickness. The bevelling should be regular, 
especially at the bottom, so as not to produce holes or 
excess of thickness at the bottom of the bevel. 

The edges to be welded and their immediate heigh- 
bourhood should be thoroughly cleaned. This can be 
done with a file, scraper, or sheets of emery. Chemical 
agents such as spirits of salt or nitric acid are some- 
times employed ; but it is preferable to precede their 
use by a mechanical cleaning. 

Before beginning the welding the parts should be 
carefully arranged so that during the welding operation 



140 SOLDERING, BRAZING AND WELDING 

they remain perfectly in position. Owing to the high 
conductivity of copper, a relatively larger blowpipe tip 
must be used than when welding either iron or mild 
steel of the same thickness. The power of a blowpipe 
of 225 litres with an approximate consumption of 7' 75 
cub. ft. of acetylene per hour would be suitable, with 
economical results, for iron or mild steel J in. thick, 
whereas for copper of the same thickness the pow T er of 
the blowpipe should be of 300 litres, having an approxi- 
mate consumption of 10' 5 cub. ft. of acetylene per 
hour. Also, a blowpipe which is too strong tends to 
melt the metal too rapidly. This should be as care- 
fully avoided as that of melting too slowly. 

A pure copper w T elding rod may be employed for 
filling in, but it is not so effective as a welding rod 
made of phosphor copper. The phosphorus is incor- 
porated in a very small quantity, so that none remains 
in the weld after its execution. A filler rod which 
contains too much phosphorus lacks fluidity, and melts 
at a temperature much lower than that of the copper 
to be welded, thus facilitating adhesion. Moreover, the 
welds in which the phosphorus remains lack elongation, 
and therefore do not possess the same mechanical pro- 
perties as pure copper. The welding rod after -3^ in. 
of its diameter should be about equal to the thickness 
of the weld, although in practice feeders about \ in. 
in diameter are not generally employed. Welds made 
on copper without a deoxidising welding rod properly 
prepared have a tendency to oxidise, and therefore do 
not possess the required qualities. In addition, the 



OXY -ACETYLENE WELDING 141 

surface of the metal must be covered with a carefully 
prepared mixture of potassium phosphate and potas- 
sium carbonate to a depth of about ye" i n - Upon the 
application of the flame, the mixture will melt and 
form a glaze over the surface of the copper, thus pre- 
venting oxidation and assuring good work. 

A flux consisting of chloride of sodium, sodium 
borate, and boracic acid is also recommended. The 
flux should be sparingly applied by dipping the end of 
the welding rod into the vessel containing the flux. 
The end of the rod should be warmed in order that the 
flux adheres. 

Before beginning the actual operation of welding, 
it is essential to raise the edges of the weld and the 
parts in the vicinity to a high temperature. The high 
conductivity of the metal necessitates this, as any 
supply of molten welding rod before the edges are in a 
molten state inevitably produces adhesion. The flame 
of the blowpipe should be perfectly regulated and main- 
tained without excess of either acetylene or oxygen. 
In executing the weld, care must be taken to avoid 
contact of the white jet of the blowpipe flame with the 
metal just about to be melted. The distance of the 
white jet should vary according to the power of the 
blowpipe, say from & in: 'to § in". If this distance is 
increased, the gases resulting from the second phase 
of combustion, carbonic acid and water vapour, in- 
fluence the weld. Care must be taken that the fusion 
of the metal should not be undertaken until the edges 
of the weld and the parts near have been raised to a 



142 SOLDERING, BRAZING AND WELDING 

high temperature. At this moment the welding rod 
and the parts to be joined should be melted simul- 
taneously. It is essential that the welding rod should 
be regularly incorporated in the line of welding, and 
must not be allowed to fall in drops. The operation 
should be continuous, taking care to attack regularly 
the two edges of the metal. The welding is thus 
executed rapidly. 

It is well known that internal strains are always 
set up in every process of welding, due to the ex- 
pansion and contraction when a metal is heated and 
cooled. Copper lacks tenacity when heated ; hence 
contraction of the metal , whose coefficient of expansion 
is also fairly high ; fractures thereby are often pro- 
duced, especially in the welded part. However, pre- 
heating the article to a high temperature, maintaining 
the heating after the operation of welding and slow 
cooling, enables one in many cases to avoid fractures 
due to contraction. It is also necessary to hammer the 
line of welding and its vicinity. After the hammering 
operation it is essential to reheat the copper, raising it 
to redness (500° C. to 600° C). Then plunge into cold 
water, or cool as rapidly as possible. The structure 
of the weld is not quite as homogeneous as other parts 
of the piece welded. This is, however, controlled 
largely by the skill and workmanship of the operator, 
who can, at will, make the weld more or less homo- 
geneous. 

It is impossible to enumerate in anything like detail 
all the work in copper which may be executed by 



OXY-ACETYLENB WELDING 143 

oxy-acetylene autogenous welding. However, copper- 
smiths are advantageously making great use of the 
syslem, thereby replacing their old methods of brazing 
and riveting. 

Welding Aluminium.— In preparing aluminium to 
be welded, the edges must first be thoroughly cleaned 
and the welding rod very pure, so as to avoid the 
incorporation of impurities, which is apt to bring 
about rapid disintegration in the line of welding. 
Bevelling the edges to be joined is not necessary below 
a thickness of J in. From J in. to -ft- in. a slight open 
bevel is sufficient, -ft in. thick and above angle of 
bevel should be about 90°. For thin sheets up to a 
maximum of 4\> in., welding is facilitated by flanging 
the edges at right angles. The depth of the flange 
should be slightly deeper than the thickness of the 
metal. By this method no welding rod is required, the 
edges being simply fused. The weld should afterwards 
be hammered level. 

Aluminium should never be welded without a flux. 
If welding is attempted without a flux, globules con- 
sisting of aluminium within and a coating of alumina 
(oxide of aluminium) will appear. In order to eliminate 
these by the blowpipe flame it would be necessary to 
raise the temperature to the melting point of the oxide 
of aluminium, which is nearly 3,000° C, whilst the 
melting point of metallic aluminium is only 657° C, 
To produce a flux which will dissolve the oxide at the 
low melting point of the metal and at the same time 
protect the hot metal from contact with the air has 



144 SOLDERING, BRAZING AND WELDING 

obviously not been a simple problem to the chemist and 
engineer. However, several good fluxes are now ob- 
tainable which enable any experienced welder to effect 
satisfactory welds in aluminium. 

A flux consisting of the following ingredients can 
be recommended : sodium chloride 30 parts, potassium 
chloride 45 parts, lithium chloride 15 parts, potassium 
fluoride 7 parts, and bisulphate of potassium 3 parts. 

When making fluxes for the welding of aluminium, 
great care is necessary in order to completely dry the 
ingredients, thus avoiding their combination with each 
other. On aluminium above -^ i n - thick, the flux is 
best 'applied by dipping the end of the w T elding rod into 
the vessel containing the flux. The end of the rod 
should be first warmed in order that the flux adheres. 
The welding rod after -^ in., its diameter should 
be just about equal to the thickness of the weld, 
although in practice feeders above J in. diameter are 
not advisable. 

In executing the weld, care must be taken to avoid 
contact of the white jet of the blowpipe flame with the 
metal just about to be melted, because the high tem- 
perature of this part tends to produce holes which are 
difficult to fill in. The distance of the white jet should 
vary according to the power of the blowpipe, say from 
J in. to f in. The flame should be so adjusted as to 
furnish an excess of acetylene. There need be but little 
fear of carbonising the metal, for the reason that the 
temperature of the work is comparatively low. For 
thin welds, up to J in. thick, it is preferable to hold 



OXY-ACETYLENE WELDING 145 

the welding rod in front of the blowpipe in the direction 
of the edges to be- welded. As soon as the latter begins 
to melt it is heated rapidly, and should be lowered to 
form one molten bath with the metal of the piece. The 
welding is thus done very rapidly. For great thick- 
nesses it is preferable to obtain fusion of the welding 
rod, previously heated in the molten bath of the bevel. 
Directly after welding, the weld should be thoroughly 
washed in clean warm water in order to remove all 
remaining traces of the flux, which would otherwise 
continue to have a chemical action on the metal, there- 
by setting up corrosion. 

Welding Cast-iron.— The edges of the weld should 
be bevelled when the thickness exceeds J in. ; this 
enables the welding to penetrate the entire thick- 
ness of the metal. Both edges must be bevelled to an 
angle of 45°, so as to form a right angle at the weld. 
The bevelling should be regular, especially at the 
bottom, so as not to produce holes or excess thickness 
at the bottom of the bevel. Workers who attempt to 
effect welds on cast-iron above, say, J in. in thickness, 
without bevelling, invariably obtain poor results, as it 
is impossible to get regular and thorough penetration. 
The bevelling of the edges may be done by chipping 
or grinding, etc. Grinding wheels made from a carbide 
of silicon abrasive are very effective for cast-iron. The 
edges to be welded and their immediate neighbourhood 
must be free from sand, dirt, and rust. 

It is known that internal strains are always set up 
in every process of welding, due to the expansion and 



146 SOLDERING, BRAZING AND WELDING 

contraction when a metal body is heated and cooled. 
These strains are not unavoidable, but their effect may 
be minimised or nullified. In the case of cast-iron, 
the tendency to crack will be greatly increased if the 
cooling of the metal after fusion is rapid or irregular. 
Consequently, the article to be welded should be pre- 
heated slowly to about 700° F. to 1,000° F. Generally 
speaking, the higher the temperature of pre-heating, 
the less the danger of cracking. Preferably, pre- 
heating and subsequent slow cooling should be carried 
out in a muffle, particularly where light and intricate 
castings have to be dealt with. 

In all cases care should be taken in the selection 

of the proper size of bknvpipe tip to be used on any 

particular job. Therefore, the size of tip recommended 

by the manufacturers should be employed. The total 

heat of fusion of cast-iron being high, it is necessary to 

use a blowpipe with a greater power than for the same 

thickness of welds on mild-steel or wrought-iron. In 

the actual operation of welding, the blowpipe flame 

should be played on the edges to be welded until the 

melting of the iron just takes place. It is essential 

to avoid contact of the white cone of the blowpipe 

flame with the metal just about to be melted ; the 

point should be kept at a distance varying from t%- in. 

to | in., according to the thickness of the work. The 

two edges to be joined should melt simultaneously. As 

soon as the first fusion is obtained, a little flux or 

scaling powder must be added ; this is usually applied 

by dipping the extremity of the welding rod into the 



OXY-ACETYLENE WELDING 147 

vessel containing the flux, the rod having been pre- 
viously heated. Avoid throwing the powder into the 
molten metal whilst executing the weld, as the supply 
from the welding rod is always sufficient. 

Many kinds of fluxes for cast-iron are furnished by 
the manufacturers of w r elding apparatus, which vary 
considerably in composition. The principle of all of 
them is to provide some chemical which, at the high 
temperature involved, will break up the oxide into its 
component parts. The following combinations will 
perform these functions, and can be recommended : 
(1) Boracic acid 80 parts, powdered chlorate of potash 
20 parts, ferric carbide 15 parts. (2) Equal parts of car- 
bonate and bicarbonate of soda, to which is added from 
10 to 15 per cent, of borax and 5 per cent, of pre- 
cipitated silica. (3) Carbonate of soda 50 per cent, and 
bicarbonate of soda 50 per cent. The necessity for using 
a flux may not be thoroughly appreciated ; but if it 
is attempted to weld cast-iron without it difficulty will 
at once be experienced. 

Do not add any metal from the welding rod until 
the bottom of the V is filled from the sides. It is 
found that by employing silicon in the welding rod, in 
the form of ferro-silicon, the iron combines with the 
silicon in preference to the carbon, allowing the carbon 
to take the form of graphite, and thus facilitate the 
formation of grey iron. The welding rod should con- 
tain about 4 per cent, of silicon and as low as possible 
in manganese. The purchase of such a welding rod is 
not at all difficult, and may be obtained from the same 



148 SOLDERING, BRAZING AND WELDING 



manufacturers as the flux, from J in. to | in. in 
diameter. 

One criticism of cast-iron welding has been directed 
against the hardness of the weld. This hardness may 
be due to a number of causes, such as inefficiency of 
the operator, unsatisfactory fluxes and welding appara- 
tus, rapid cooling, etc. Therefore, as stated previously, 
in order to get good workable welds, there must be slow 
cooling after the welding is complete ; and there is no 
reason why the w r orker who carefully follows the in- 
structions given, and applies himself diligently to the 
task, should not be able to weld cast-iron of any thick- 
ness in an efficient and workmanlike manner. 

This method of welding cast-iron successfully solves 
an unlimited variety of manufacturing and repair prob- 
lems in the engineering industry, and can be relied 
on to make homogeneous welds on cast-iron. It is im- 
possible to enumerate in anything like detail all the 
work in cast-iron which may be executed by oxy- 
acetylene welding ; but the following are some of the 
applications for which it has already been advan- 
tageously employed : For repairing broken machine 
parts, gear boxes, motor cylinders, crank cases, tanks, 
manifolds, flywheels, etc., filling blowholes and defects 
in castings. Castings impossible or difficult to mould 
can be made in parts and united. Teeth broken from 
gear wheels can be renewed, and adding metal in any 
desired quantity to worn parts of cast-iron articles. 
As a concrete example of its economical and positive 
aid to the engineering industry, the following may be 



OXY-ACETYLENE WELDING 149 

of interest. A cast-iron belt- wheel would have gone 
on the scrap heap, a total loss, with four of the six 
spokes broken, three entirely out. It was 5 ft. in 
diameter, and weighed about 500 lb. , but was not worth 
much as scrap metal. Scrapping it meant the pur- 
chase of a new wheel, and perhaps a long delay in get- 
ting one cast. But with the oxy-acetylene process the 
three spokes that were fractured were welded into 
place ; the fourth spoke broken near the hub was also 
welded. There were seven welds, each about 1J in. 
by 4 in. ; the job was done profitably at a cost of £5, 
ready for delivery in two days, and was considerably 
better than buying a new wheel, and waiting two weeks 
or two months for delivery. The process is particularly 
suitable for this class of work, and cannot fail to give 
satisfaction if performed by an experienced welder. 
The cost of welding a given job depends not only on 
its thickness, but on the skill of the workman. For 
example, the same class of job may vary as much as 
50 per cent, if executed by different operators. 



CHAPTEE XVII 

Lead Burning 

Lead-bukning or flaming is the autogenous welding 
of lead by means of either an aero-hydrogen or oxy- 
coal-gas blowpipe flame. In the past the apparatus 
required included a hydrogen-gas generating chamber 
(called the "lead-burning machine") and a blower 
or air chamber. The hydrogen was made by the action 
of dilute sulphuric acid on zinc. That system is now, 
or should be, obsolete, having been superseded by the 
cleanly and altogether more convenient process of em- 
ploying two cylinders, one of compressed coal-gas and 
the other of compressed oxygen, in conjunction with an 
injector-pattern blowpipe. Gauges and regulators are 
required as in the oxy-acetylene process. 

The oxy-acetylene process may be successfully 
applied to lead-burning in spite of the great heat 
of such a flame. The consumption of acetylene, 
according to Mr. D. Richardson's translation of 
Granjon and Rosenberg's French work, is only 1 to 2 
cubic feet per hour for lead -^ in. to -ft in. thick, 
and the process is stated to have "considerable 
advantages over all other methods of autogenous 
soldering." 

In lead-burning it is customary to employ a tri- 
angular stick of refined lead for filling up the seams. 

150 



LEAD BURNING] 151 

By being burnt or joined together in this way, the lead 
becomes homogeneous, and the various parts of it 
equally, withstand the same chemical action and heat. 
For this reason it is used for joining the seams of 
chemical and acid tanks, and for the joints of pipes 
used for the conveyance of such chemicals. Solder 
being an alloy, the acid would have a solvent action on 
it, eating it away and rendering it useless, and it would 
also give rise to electrical action, practically impossible 
when only one metal is exclusively employed. Lead- 
burning is also often used on external or roof work. 

The seams burnt on sheet-lead are of two kinds : 
one forming a butted joint, the other a lapped joint. 

In burning a butted seam, the two edges of the lead 
to be joined are butted together, and shaved about 
J in. to § in., or slightly less, on each side. The gas 
and oxygen are turned on and adjusted so as to produce 
a flame from about 5 in. to 6 in. long, and tapering to 
a fine point. The hottest part of the flame is the centre 
of the thickest portion, about 1 in. or 1J in. from the 
jet. Hold the jet in the right hand, and a strip of 
lead in the left, and allow the flame to play on the 
end of the strip, which is held just above the seam. 
As the strip melts, the jet is diverted on to the seam 
so as to fuse the edges together, the additional lead 
forming a thickened portion. The strip is again melted, 
and joined to the edges, and also to the thickest part ; 
and so on along the length. Care should be taken to 
burn the lead through, but not for the metal to flow 
beneath the seam. After a little practice, the operator 



152 SOLDERING, BRAZING AND WELDING 

will know exactly when to apply and when to remove 
the jet. 

Fig. 73 shows a flat butted joint partly burnt. The 
stick of lead is just nipped with the flame, and a bead 
of lead dropped on the seam. The flame is then 
directed on to this bead until it is fused with the seam. 
When bead and seam are melted together, the flame 
is immediately raised. The next bead of lead is then 
dropped on the seam so as to half cover the previous 
bead, as show 7 n at m (Fig. 73). The flame is then 
directed on the second bead, the flame being immedi- 
ately raised after these are fused together, and this 
operation is repeated until the whole of the seam is 
burnt. 

A flat lapped joint, partly burnt, is shown by 
Fig. 74. In burning this joint, the stick of lead is 
only required to fill up any irregularities in the burning, 
and is not required to form the seam in the same way 
as it is in a butted joint, because in lapped burning 
the overcloak is burnt down on to the undercloak, as 
shown in Fig. 75. In horizontal and vertical burning, 
lapped joints only should be used. 

Fig. 75 shows a specimen of horizontal or side burn- 
ing, and Fig. 76 one of vertical or upright burning. In 
burning both of these, the stick of lead is not required 
at all, the overcloak being in each case burnt down 
on to the undercloak. Care must be taken that both 
the overcloak and undercloak of a lapped joint are well 
shaved. 

The seams should not be soiled or greased, and care 



^^2 



Fig. 73.— Butted Seam 
Partly Burnt 




umtiWTi 



3c 



Fig. 75. — Horizontal 
or Side Burning 



S^ 



Fig. 74. — Lapped Seam 
Partly Burnt 




/ 



Fig. 76. — Vertical or 
Upright Burning 



Fig. 77.— Burning 
Upright Joint 




L vvv Awmww^^^^mwv\ ,' 



Fig. 78. — Branch Joint 
Ready for Burning 



154 SOLDERING, BRAZING AND WELDING 

must be taken not to tarnish them in any way. If the 
lead is not shaved quite clean, or it becomes tarnished 
after it is shaved, it will be found difficult to burn 
it together successfully. No tallow or smudge is neces- 
sary. The operator will soon detect the presence of 
any foreign substance or dirt on the lead, and the 
shavehook should be kept handy to remove it. 

In burning a vertical lapped seam, starting at the 
bottom, the lapping lead is melted, and as it runs is 
turned on to the back portion and fused into it. A 
slight projection is formed, which holds the next melt- 
ing, and so on, each layer forming a base for the next, 
and adding to the height until the top is reached. 

In practising either horizontal or vertical burning, 
the student should first place his work at an easy angle 
— say, at about 25° or 30° — gradually raising it as 
he becomes proficient until the seam is in a hori- 
zontal or vertical position as desired. Two surfaces 
can he burned together in any position — horizontal, 
vertical, or even overhead, where soldering would be 
impossible. 

Pipe joints can also be made by burning. First 
one pipe is opened to form a socket like a slip joint. 
The male part, which must enter at last f in., must 
be well shaved and made to fit tight. Fig. 77 shows an 
upright joint prepared and partly burnt. Fig. 78 shows 
a section of a branch joint as prepared for burning. 
Care must be taken to work up a good thick shoulder 
for the socket N. 



INDEX 



Acetylene used in welding, 135 
Alloys, eutectic, 4 
Aluminium, bit used with, 61 
— , difficulty in soldering, 57, 58 

, flux for, 61, 143, 144 

, oxy-acetylene welding, 143 

, soldering, 62, 63 

solders, 58-61 

Arc welding, 131, 132 
Autogenous welding (see Oxy- 
acetylene welding) 

" Best " solder, 4 
Birdcage wires, soldering, 53 
Bismuth, solder and flux for, 7 
Black, plumber's, 66-68 
Blow-lamp bit, 21 
Blow-lamps, 44, 46, 92 

, managing, etc., 118-121 

■, paraffin brazing, 122-128 

Blowpipe, bench, 40, 41 
, Black's, 37 

capacities, 116 

flame, 38 

, Fletcher's, 37 

, gas, making, 93, 94 

, mouth, 37-40 

, operating, 46 

-, oxy-acetylene, 136 

■: proportion of air to gas, 114 

soft solder, 4 

- soldering, 17. 46-56 
Boiling water, solders that melt 

in, 11 
Borax flux, 78, 79 
Brass fittings, tinning, 66 

, solder and flux for, 7 

-, soldering aluminium to, 60 

Britannia metal, solder and flux 

for, 7 
Brazing, 1, 89-107 
■ copper rod, 100 

cycle-frame joints, 103 

, flux for, 91 

iron, 98-100, 105-107 

- key stems, 101 

, spelter for, 89-91 

steel, 98-100 

Brazing-lamps (sec Blowlamps) 
Brooches, soldering, 83 
Brush for applying flux, 14 
Bunsen burner, 40. 42 
Burning lead, 2, 150-154 

Cast-iron, brazing, 105-107 

, flux for, 106, 107, 147 

, oxy-acetylene welding, 145 

Catching-tray, 42 
Churns, soldering, 35 
Clay, packing work in. 51 
Cloths, plumber's, 68, 69 



"Coarse" solder, 4 

" Common " solder, 4 

Compo. piping, making solder 

from, 9 
Contact welding, 129-131 
Copper, brazing, 100 

, flux for, 141 

, oxy-acetylene welding, 139 

i soldering aluminium to, 60 

, soft solder and flux for, 7 

Copper-bit soldering, 28-36 
Copper-bits, 17-24 

, gas-heated, 22-24 

, holding, 30 

, spirit-heated, 20, 21 

, stoves for, 24, 25 

, tinning, 25-28 

Corroded metal, soldering, 50 
Cycle brazing, 102-105 

Dial ring, soldering, 50 
Dross on solder, 11 

Electric arc welding, 131, 132 

contact welding, 129-131 

Enamelled ware, soldering, 35 
Eutectic alloys, 4 

" Fine " solder, 4 
Flaming lead, 2, 150-154 
Flux (see also names of metals) 

, applying, 14, 15 

for brazing, 91 

combined with solder, 10 

containers, 14 

for soft soldering, 12-16 

Fluxite and specialities, 13, 20 
Food containers, flux for, 15 
Fusion welding (see Oxy-acety- 
lene welding) 

Galvanised steel, solder and flux 

for, 7 
Gas blowpipes, 41, 93, 94, 112-117 
- — — brazing-hearth, 94-98 
Gas-heated bits, 22-24 
Gold, " colouring," 87, 88 
— , flux for, 7 

jewellery, soldering, 83-88 

solders, hard, 85, 86 

-— , soft, 7 

Gold-cased ware, soldering, 84 
Granulated solder, 8 
Gun-barrel, soldering catch on, 

36 
Gunmetal, solder and flux for, 7 

Hard solder and soldering (see 
Brazing, Silver-soldering, and 
names of metals) 

Hardness of solder, 5 



*55 



156 



INDEX 



Hearth, gas brazing, 94-98 
Hiorns, A. H., 4, 5 

Iron, brazing, 98-100, 105-107 

, flux for, 147 

, hammer- welding, 108 

■ , oxy-acetylene welding, 145 

, soft solder and flux for, 7 

Jewellery, soldering, 83-88 
Joints, reinforced and filled-in, 34 
Jubb, W. H., 76 

Kettle ispout, soldering, 50 
Key stems, brazing, 101 
" Killed spirit," 12-15 

Lading-can handle, soldering, 47 
Ladle, solder, 7 
Lamp, soldering lug on, 48 
Lead, solder and flux for, 7 
Lead-burning, 2, 150-154 
Leaded lights, soldering, 35 

" Magic " solder, 10 

" Medium " solder, 4 

Melting points of solder, etc., 4, 5 

Milk churns, soldering, 35 

Name-plates, sweating letters on, 
54-56 

Oxy-acetylene welding, 2, 134-149 

aluminium, 143-145 

■ : apparatus, 136-139 

cast-iron, 145-149 

— — copper, 139-143 

Oxygen used in welding, 135 

Paillons, solder, 79-80 

Pewter, making solder from, 9 

, solder and flux for, 7 

Phosphor-tin, solders containing, 

59-61 
Pickle, gold-solderer's, 85, 87 

, silver-solderer's, 77, 78, 87 

Pipe joints, burnt, 153, 154 

, horizontal or under- 

hand wiped, 69-72 
: lead to cast-iron. 74 

, silver-soldered, 80, 81 

, soldered, 52, 53 

, upright wiped, 72-74 

Plumber's black, 66-68 

cloths, 68, 69 

flux, 66 

solder. 4, 64-66 

" Poisoned '• solder, 6, 65, 66 

Rings, jewelled, soldering, 84 
Ryan's gas-heated bit, 22 

Sal-ammoniac block for tinning 
bits, 26-28 



Sand, packing work in, 51 
Seams, soft-soldered, 31-33 
Shave-hook, 28 
Silver jewellery, soldering, 83 

, soft solder and flux for, 7 

■ solders, 75-77 

Silver-soldering, 1, 3, 75-82 

: pickle, 77, 78 

: quenching, 81 

■ : removing marks, 81 

Smudge, plumber's, 66-68 
Soft soldering, 1-3, 28-56 

with blowpipe, 46-56 

■ copper-bit, 28-36 

■ solders, 4-11 

■ ■ that melt in boiling 

water, 10, 11 
Soil, plumber's, 66-68 
Solder (see also Silver solder, Soft 

solder, etc., and under names 

of metals) 

combined with flux, 10 

, overheated, 11 

•, re-melted, 11 

" Soldering iron," 17 
Soldering solutions, 14 
Spelter, 1, 3, 89-91 
Spirit-heated bits, 20, 21 
Spirit-lamps, 40 
Spot-welding, electric, 130 
Steel, brazing, 98-100 

, flux for, 111 

, hammer-welding, 109-111 

, soft solder and flux for, 7 

Stoves for heating bits, 24, 25 
Strip solder, 6-8 
Sweating, 32-34, 54-56 

Tapers, 41 

Tears, solder, 8 

Thermit welding, 2, 132, 133 

Tin, solder and flux for, 7 

Tinning bits, 25-28 

" Tinol " specialities, 10, 13, 19 

Tinplate, solder and flux for, 7 

" Touch " or tallow, 66 

Tube solder, 10 

Vegetable masher, soldering, 48 
" Very fine " solder, 4 

Watch-case, silver-soldering, 79 
Welding (see also separate headings) 

■ , electric, 129-132 

■ iron and steel under the 

hammer, 108-111 

, oxy-acetylene, 134-149 

, thermit, 132, 133 

: various processes, 1, 2 

Wire, solder, 8 

Zinc chloride, 12-15 

in solder, 6, 65, 66 

, solder and flux for, 7 



Printed by Cassell 



Company, Limited, La Belle Sauvage, London, E.C. 
F30.816 



